SHCHEPINOV MIKHAIL S (GB)
| WO2007102030A1 | 2007-09-13 |
RAAP, J. ET AL.: "Enantioselective syntheses of isotopically labeled a-amino acids. Preparation of (epsilon-13C)-L-alpha-aminoadipic acid and five isotopomers of L-lysine with 13C, 15N and 2H in the delta- and epsilon-positions", RECUEIL DES TRAVAUX CHIMIQUES DES PAYS-BAS, vol. 109, no. 4, 1990, pages 277 - 286, XP008143266
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REN, C. ET AL.: "Simultaneous metabolic labeling of cell with multiple amino acids: localization and dynamics of histone acetylation and methylation", PROTEOMICS: CLINICAL APPLICATIONS, vol. 1, no. 1, 2007, pages 130 - 142, XP008143255
SCHOLL, P. F. ET AL.: "Synthesis of 5,5,6,6-D4-L-lysine-aflatoxin B1 for use as a mass spectrometric internal standard", JOURNAL OF LABELLED COMPOUNDS & RADIOPHARMACEUTICALS, vol. 47, no. 11, 2004, pages 807 - 815, XP008143256
BRANDL, M. ET AL.: "The biosynthesis of 3-(trans-2-Nitrocyclopropyl)alanine, a Constituent of the Signal Metabolite Hormaomycin", EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, no. 1, 2004, pages 123 - 135, XP008143257
TANG, K.-H. ET AL.: "Kinetic and biochemical analysis of the mechanism of action oflysine 5,6- aminomutase", ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS, vol. 418, no. 1, 2003, pages 49 - 54, XP004455790
CHO, Y. R. ET AL.: "Cooperativity and anti-cooperativity between ligand binding and the dimerization ofristocetin A: asymmetry of a homodimer complex and implications for signal transduction", CHEMISTRY & BIOLOGY, vol. 3, no. 3, 1996, pages 207 - 215, XP026897142
KELLAND, J. G. ET AL.: "Stereochemistry of Lysine Formation by meso-Diaminopimelate Decarboxylase from Wheat Germ: Use of 1H-13C NMR Shift Correlation To Detect Stereospecific Deuterium Labeling", BIOCHEMISTRY, vol. 24, no. 13, 1985, pages 3263 - 2367, XP008143026
ASADA, Y. ET AL.: "Stereochemistry of meso-alpha,epsilon-Diaminopimelate Decarboxylase Reaction: The First Evidence for Pyridoxal 5'-Phosphate Dependent Decarboxylation with Inversion of Configuration", BIOCHEMISTRY, vol. 20, no. 24, 1981, pages 6881 - 6886, XP008143027
See also references of EP 2268604A4
| WHAT IS CLAIMED IS:
1. A composition comprising
FORMULA II FORMULA III wherein D is deuterium; and wherein a carbon in Formula (I), (II), or (III) is optionally carbon-13; wherein the carbon-13, deuterium or both are enriched at least 20% more individually or collectively in comparison to naturally occurring carbon-13, deuterium or both at the same positions in the compound.
2. The composition of Claim 1 , wherein at least one carbon is carbon-13.
3. The composition of Claim 1 or 2 wherein the carbon-13, deuterium or both is enriched greater than 50% more than the naturally occurring carbon-13, deuterium or both at the same position(s) of the compound.
4. The composition of Claim 1 or 2 wherein the carbon-13, deuterium or both is enriched greater than 2X the naturally occurring prevalence of the carbon-13, deuterium or both at the same position(s) of the compound.
5. The composition of Claim 1 or 2 wherein the carbon-13, deuterium or both is enriched greater than 1 OX the naturally occurring prevalence of the carbon-13, deuterium or both at the same position(s) of the compound.
6. The composition of Claim 1 or 2 wherein the carbon-13, deuterium or both is enriched greater than IOOX the naturally occurring prevalence of the carbon-13, deuterium or both at the same position(s) of the compound.
7. A method of treating a condition associated with degradation of lysine-containing moieties in vivo comprising administering to a subject in need thereof the composition of any of Claims 1-6.
8. A method of inhibiting the effect of any LOX enzyme on lysine comprising administering to a subject in need thereof the composition of any of Claims 1-6.
9. A pharmaceutical formulation comprising the composition of any of Claims 1 -6 and a pharmaceutically acceptable carrier.
10. Use of the pharmaceutical formulation of Claim 9 to treat a condition, the etiology of which is associated with degradation of lysine-containing moieties in vivo.
11. The method of Claim 7 or 8, wherein the subject is treated for a condition associated with oxidized forms of lysine-containing moieties in vivo by stabilizing lysine against degradation.
12. A method comprising administering to a subject foodstuffs, supplement, or a pharmaceutical formulation containing non-naturally-occurring heavy isotope prevalences greater than 20% more than the level of naturally occurring heavier isotope, wherein heavy isotopes are incorporated in vivo to produce the composition according to Claim 1 or 2.
13. The method of Claim 12 wherein the non-naturally-occurring heavy isotope prevalences are greater than 50% more than the level of naturally occurring heavier isotope.
14. The method of Claim 12 wherein the non-naturally-occurring heavy isotope prevalences are greater than 2X the level of naturally occurring heavier isotope.
15. The method of Claim 12 wherein the non-naturally-occurring heavy isotope prevalences are greater than 5X the level of naturally occurring heavier isotope.
16. The method of Claim 12 wherein the non-naturally-occurring heavy isotope prevalences are greater than 1OX than the level of naturally occurring heavier isotope.
17. The method of Claim 12 wherein the non-naturally-occurring heavy isotope prevalences are greater than I OOX the level of naturally occurring heavier isotope.
18. The method of any one of Claims 1 1-17, wherein stabilizing lysine containing moieties via non-naturally occurring levels of heavy isotope reduces tumor growth in a subject.
19. The method of any one of Claims 1 1-18, wherein stabilizing lysine containing moieties via non-naturally occurring levels of heavy isotope reduces angiogenesis in a subject.
20. The method of any one of Claims 1 1-19, wherein stabilizing lysine containing moieties via non-naturally occurring levels of heavy isotope reduces fibrosis in a subject.
21. A method of reducing growth of a tumor in a subject, comprising administering a compound of any one of Claims 1-6 to the subject.
22. The method of Claim 20 or 21. wherein said tumor is a primary tumor or a metastatic tumor.
23. The method of Claim 20 or 21, wherein said tumor is selected from among lung cancer (including lung adenocarcinoma, squamous cell carcinoma, large cell carcinoma, bronchioloalveolar carcinoma, non-small-cell carcinoma, small cell carcinoma, mesothelioma); breast cancer (including ductal carcinoma, lobular carcinoma, inflammatory breast cancer, clear cell carcinoma, mucinous carcinoma,); colorectal cancer (colon cancer, rectal cancer); anal cancer; pancreatic cancer (including pancreatic adenocarcinoma, islet cell carcinoma, neuroendocrine tumors); prostate cancer; ovarian carcinoma (ovarian epithelial carcinoma or surface epithelial-stromal tumour including serous tumour, endometrioid tumor and mucinous cystadenocarcinoma, sex-cord-stromal tumor); liver and bile duct carcinoma (including hepatocelluar carcinoma, cholangiocarcinoma, hemangioma); esophageal carcinoma (including esophageal adenocarcinoma and squamous cell carcinoma); bladder carcinoma; carcinoma of the uterus (including endometrial adenocarcinoma, uterine papillary serous carcinoma, uterine clear-cell carcinoma, uterine sarcomas and leiomyosarcomas, mixed mullerian tumors), glioma, glioblastoma, medullablastoma, and other tumors of the brain; kidney cancers (including renal cell carcinoma, clear cell carcinoma, Wilm ' s tumor); cancer of the head and neck (including squamous cell carcinomas); cancer of the stomach (stomach adenocarcinoma, gastrointestinal stromal tumor); multiple myeloma; testicular cancer; germ cell tumor; neuroendocrine tumor; cervical cancer; carcinoids of the gastrointestinal tract, breast, and other organs; signet ring cell carcinoma; mesenchymal tumors including sarcomas, fibrosarcomas, haemangioma, angiomatosis, haemangiopericytoma, pseudoangiomatous stromal hyperplasia, myofibroblastoma, fibromatosis, inflammatory myofibroblastic tumour, lipoma, angioiipoma, granular cell tumour, neurofibroma, schwannoma, angiosarcoma, liposarcoma, rhabdomyosarcoma, osteosarcoma, leiomyoma, leiomysarcoma and non-Hodgkin's lymphoma.
24. The method of any one of Claims 20-23, wherein the tumor in the subject is reduced by at least 10%, 25%, 50%, 70%, 90%, 95%, or more as compared to the tumor in the subject prior to treatment.
25. The method of any one of Claims 20-24, where in the survival of a subject with a tumor is increased by at least 10 days, 1 month, 3 months, 6 months, 1 year, 2 years, 5 years, 10 years, or more compared to a subject that is not administered the composition.
26. The method of any one of Claims 20-25, wherein metastatic tumor burden of a subject is stabilized.
27. The method of Claim 26, wherein the metastatic tumor burden is stabilized for at least 10 days, 1 month, 3 months, 6 months, 1 year, 2 years, 5 years, 10 years or more.
28. A method of inhibiting angiogenesis in a subject comprising, administering or composition of any one of Claims 1-6 to the subject.
29. A method of inhibiting a fibrotic disease in a subject by administering the composition of any one of Claims 1-6 to the subject.
30. The method of Claim 29, wherein said fibrotic disease is a liver fibrosis, a lung fibrosis, a kidney fibrosis, a cardiac fibrosis or scleroderma.
31. The method of Claim 30, wherein said kidney fibrosis is diabetic nephropathy, glomerulosclerosis, diabetic nephropathy, vesicoureteral reflux, tubulointerstitial renal fibrosis or glomerulonephritis.
32. A method of decreasing extracellular matrix formation by contacting a sample or cellular tissue with the composition of any one of Claims 1-6.
33. The method or use of any one of Claims 7-32 wherein the administration or contacting is by parental administration.
34. The method or use of any one of Claims 7-32 wherein the administration, or contacting is by ingesting a supplement, food, or oral pharmaceutical composition.
35. The method or use of any one of Claim 7-34 in combination with another anticancer or anti-fϊbrotic disease therapy. |
THERAPIES FOR CANCER USING ISOTOPICAIXY SUBSTITUTED LYSINE
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. provisional application number 61/036,841 (Atty Docket No. RETOP.002PR) which is incorporated herein by reference.
BACKGROUND
[0002] Lysyl oxidases (LOX, LOXL, LOXL2, etc.; amine oxidase family) are Cu- dependent enzymes that oxidize lysine into allysine (α-aminoadipic-δ-semialdehyde) [Kagan HM. et al, J. Cell. Biochem. 2003; 55:660]. LOX have been implicated in crosslink formation in stromal collagens and elastins. LOX are elevated in hypoxic tumors and affect cell motility, tumor development and progression of metastasis [Kirschmann DA. et al, Cancer Res. 2002; (52:4478]. This elevation is mechanistically important for breast cancer metastasis and invasion as well as in other cancers including colon and esophagus [Fong SF, et al. genes Chromosomes Cancer 2007; 6:644], and is based on the foπnation of Schiff-base linkages (aldehyde + amine) or aldol condensation products (aldehyde + aldehyde), allowing cancer cells to latch on to other cells/tissues. There are other mechanisms of LOX involvement into metastasis progression- for example, the recruitment of bone marrow- derived cells [Erler JT et al. Nature 2006; 440: 1222-1226; Erler JT. et al., Cancer Res. 2006; 66: 10238: Erler JT et al. Cancer Cell 2009; 75:35-44] for a so-called premetastatic niche foπnation.
|0003] LOX oxidises Lys of collagens, elastins and other proteins to allysine and/or
L-Lysine Allysine 5-Hydroxy-L-lysιne
[0004] 5-hydroxylysine. These can then foπn cross-links, for example as shown below:
Desmosine lsodesmosine
[0005] A reaction important in metastatic development. It is therefore desirable to reduce the activity of lysyl oxidase in cancer. As with any cancer treatment, it is also desirable that this does not completely block the enzyme activity, so as to minimize the adverse effects of therapy on other aspects of physiology.
|0006) It is therefore desirable to reduce the activity of extracellular LOX in cancer. Some current approaches involve LOX inhibitors (e.g. β-aminopropionitrile [Jackson LE. et al., Biochem. Biophys. Res. Commun. 1991 ; 179:939]), sequestration of Cu, and the use of antibodies [Erler JT et a!., Nature 2006; 440:1222]. As with any cancer treatment, it is also desirable that this does not completely block the enzyme activity, so as to minimize the adverse effects of therapy on other aspects of physiology. For example, inhibition of LOX is known to cause increased elasticity of blood vessels etc., leading to aneurisms. Besides, these methods are likely to be immunogenic, as well as bringing further complications such as toxicity.
[0007] It is known that the rate of some reactions breaking or forming chemical bonds is affected by the nature of the isotopes of the atoms, which the bond links. In general, bonds terminating in a heavy isotope will be less liable to cleavage than a bond terminating in a lighter isotope. Of particular note is that bonds between hydrogen atoms and other atoms are less liable to breakage if the hydrogen is 2 H rather than 1 H. A similar effect is seen when comparing the rate of cleavage of a bond between a carbon atom and another atom, where bonds with l j C are less liable to cleavage than bonds with 12 C. This is known as the Kinetic Isotope Effect, and is well described. Many isotopes are known to show this effect, as is described in Isotope effects in chemical reactions. (CJ. Collins, N. S. Bowman (eds.) 1970). It is known that these effects are also manifest in enzyme-catalyzed reactions, as described in.
Isotope effects on enzyme-catalyzed reactions (Cleland, W.W., M.H. O'Leary, and D.B. Northrop (eds.) 1976).
SUMMARY
[0008] The KIE may be used to reduce the activity of lysyl oxidase without blocking its activity. Embodiments of this invention provide for 2,6-diamino-6,6- dideuterohexanoic acid; 2,6-diamino-5,5,6,6-tetradeuterohexanoic acid or their esters or amides, and for the use of such compounds in a treatment for a disease in which lysyl oxidase is important.
[0009] Embodiments of the invention also provide for administering supplementation by any compounds containing higher than naturally occurring prevalences of isotopes that yield stabilization of lysine via the kinetic isotope effect via incorporation of the higher than naturally occurring heavy isotope into the lysine-containing moieties in the body according to the Formulae I, II, and III described below for stabilized lysine.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0010] In one aspect, a compound has the structure according to Formula (I)
O
LJ-I U 2 I
NH
R i FORMULA (I)
|0011] wherein either D 1 or D 2 or both Dj and D 2 are deuterium ( 2 H); wherein Ri is H or a blocking group, wherein; R 2 is an amino acid or a peptide or a protein or part of a protein, or an aliphatic, aromatic, or substituted aliphatic or substituted aromatic acyl group.
[0012] The composition is not a naturally occurring composition such as lysine or lysine derivatives, which contain a mixture of components, which contain heavy and light isotopes. The amount of heavy isotopes in the composition will be greater than the natural occurrence, such as an enrichment that is greater than 20% more than the naturally occurring heavy isotope. The heavy isotope enrichment may be an enrichment at a single position or several positions.
[0013] It will be understood by one skilled in the art that the term "blocking group" is any group which can be linked to an amino or a carboxylate function and which is likely to be cleaved enzymatically or chemically in vivo to yield the free amine or carboxylic acid respectively, or which can be displaced in vivo to make a naturally occurring metabolite of the amino acid. Such groups could comprise an amino acid, a peptide, a protein or part of a protein, an ester (e.g., linking R 2 to an alcohol or phenol), an amide (e.g., linking R 2 to an amine or Ri to a carboxylate group), or other more complex groups such as BOC, Fmoc or other well-known groups.
[0014] It will be appreciated by one skilled in the art that the term Deuterium in some embodiments refers to cases where the majority of molecules in a preparation have 2 H in the relevant position in the molecule, but that there will be in the preparation a minority of molecules where there is a 1 H in that position.
[0015] In a further embodiment, the invention also provides for the compounds of Formulae II and III, which have other carbon atoms protected with deuterium. It may also be
FORMULA II FORMULA III desirable to use carbon-13 instead of carbon- 12, for example, at position 6, or for 1, 2, 3, 4, 5, or 6 carbon atoms of Lys, to further increase the KIE.
10016] In further embodiments, the compound or a mixture of compounds of Formula (I-III) may be used in a foodstuff, and are useful for the delay of the development of cancer, or any other disease associated with enhanced activity of lysine degrading enzymes or degraded forms of lysine itself.
10017] In a further embodiment, the use of a compound or a mixture of compounds of Formula (I) may be used in a nutritional supplement for the treatment of a disease. Such supplement may consist substantially of compounds according to Formula (I) or may have such compounds as a minor component, providing that compounds of Formula (I) provide the majority of the lysine in the supplement by mass.
[0018] In a further embodiment, this invention provides for a medicament including a compound of Formula (I) useful for the treatment of a disease. The medicament may consist of a compound or a mixture of compounds according to Formula (I) in a pharmaceutically acceptable salt. The medicament may also include bulking agents or fillers, excipients, agents to assist or retard solution of the compounds according to Formula (I), agents to modify or mask taste, agents to assist in the manufacture of tablets or capsules, agents to protect the compounds during gastrointestinal transit and other materials well- known to those ordinarily skilled in the art of drug formulation. The medicament may be in the form of a powder, a table, a capsule, a liquid suitable for injection or injection, a spray, a cream, an ointment, an aerosol, a suppository or other forms well known to those skilled in the art.
|0019] In a further embodiment, this invention includes methods of administering or dosing non-naturally occurring levels of heavy isotope to subjects such that the stabilized compositions of Formula I, II, or III result. Subjects may include mammals such as humans, livestock, and laboratory animals, such as mice, rats, rabbits, monkeys or other lower order animals.
|0020] Combination therapies with e.g. known anti-cancer or anti-fibrotic treatment are also contemplated.
[0021] In some embodiments, a subject may be administered, for example, about 10%, 20%. 50%, 200% or 1000% of the average dietary content of lysine, so as to either compete with dietary lysine of the naturally occurring composition or overwhelm it. Normal dietary levels are approximately 2-3 grams per day, and of course vary with diet. For example, a subject may be administered a catalytic amount of about 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8. or 0.9 grams of lysine or lysine derivative per day described herein with greater than the natural occurrence of heavy isotope: a competitive amount of about 1, 2, 3, or 4 grams of lysine or lysine derivative per day described herein with greater than the natural occurrence of heavy isotope; or an overwhelming amount of about 4, 5, 6, 7, 8, 9, 10, 1 1 , 12, 13, 14, 15, 16, 17, 18, 19, 20, 30, 40, 50, 60, 70, 80, 90, or 100 g of lysine or lysine derivative described per day herein with greater than the natural occurrence of heavy isotope.
[0022] A further aspect of the invention provides a pharmaceutical composition of the compound or composition described herein.
[0023] A pharmaceutical composition containing the active ingredient may be in a form suitable for oral use, for example, as tablets, troches, lozenges, aqueous or oily suspensions, oil-in-water emulsions, dispersible powders or granules, emulsions, hard or soft capsules, or syrups or elixirs. Such compositions may contain excipients such as bulking agents, solubilisation agents, taste masking agents, stabilisers, colouring agents, preservatives and other agents known to those ordinarily skilled in the art of pharmaceutical formulation.
[0024] A pharmaceutical composition containing the active ingredient may also be administered in the form of suppositories for rectal administration of the drug. These compositions can be prepared by mixing the drug with a suitable non-irritating excipient, which is solid at ordinary temperatures but liquid at the rectal temperature and will therefore melt in the rectum to release the drug. Such materials are cocoa butter and polyethylene glycols.
[0025] A phaπnaceutical composition may also be suitable for delivery by inhalation to the nose, throat or lungs. Such compositions may be prepared by pre-forming compounds of the invention into particles suitable for inhalation together with other materials, or dissolving compounds of the invention in a material suitable for forming an aerosol.
[0026] A pharmaceutical composition may also be suitable for delivery by topical application, as a spray, cream, ointment, lotion, or as a component or additive to a patch, bandage or wound dressing. In addition the compound can be delivered to the site of the disease by mechanical means, or targeted to the site of the disease through the use of systemic targeting technologies such as liposomes (with or without chemical modification that provides them with affinity for the diseased tissue), antibodies, aptamers, lectins, or chemical ligands with affinity for aspects of the diseased tissue that are less abundant or not present on nonnal tissue.
[0027] A phannaceutical composition of the invention may also be in a form suitable for administration by injection. Such compositions may be in the form of a solution, a suspension or an emulsion. Such compositions may include stabilizing agents,
antimicrobial agents or other materials to improve the function of the medicament. This invention also encompasses dry, desiccated or freeze-dried forms of compounds of the invention, which can readily be formed or reconstituted into a solution suspension or emulsion suitable for administration by injection, or for oral or topical use. EXAMPLES
[0028] Deuterated Lysine was synthesised from L-Lys as shown below:
Boc.O, Et 5 N 92% DMF
D 2 , AcOD. Ptθ :
79%
EXAMPLE 1 (S)-6-trifluoroacety]amino-2-aminohexanoic acid (2)
|0029] Sodium (4.6 g; 0.2 mol) was dissolved in 200 ml of ethanol (abs). To this solution, 18.25 g (0.1 mol) of lysine (Sigma-Aldrich) hydrochloride (1) was slowly added with stirring. The mixture was stirred for 1 hour, and the precipitate filtered away. To the remaining solution cooled on ice, 21.3 g (0.15 mol) of ethyltrifluoroacetate was slowly added with intense stirring. The solution was brought up to rt and stirred for another 2 hours. 6 g (0.1 mol) of AcOH was added, and the precipitate formed was washed with EtOH and acetone. Yield: 15 g (62%). MALDI-TOF, positive mode: 242.455 (Ml + 1 ; 67%). EXAMPLE 2 (S)-6-trifluoroacetylamino-2-(ter/-butoxycarbonylamino)-hexa noic acid (3)
[0030] To compound (2) (3.63 g; 0.015 mol) suspended in 40 ml DMFA, 3.03 g (0.03 mol) of TEA and 3.6 g (0.0165 mol) of di-/er/-butylcarbonate were added, and the
reaction mixture was stirred for 3 hours at rt. The mixture was then diluted 3-fold by water and acidified by HCl to pH 2. The product was extracted with EtOAc (100 ml), washed with water, brine and dried (MgSO 4 ). The solvent was removed in vacuo to yield 4.7 g (92%) of the title compound. The analytical data for (3) was identical to that reported in literature. EXAMPLE 3 (S)-2-(fer/-butoxycarbonylamino)-5-cvanopentanoic acid (4)
[0031] To a solution of 0.56 g (0.014 mol) of NaOH in 40 ml of water, 2.39 g (0.007 mol) of compound (3), 0.2 g Of NiSO 4 x 7 H 2 O, and 3.33 g (0.014 mol) of sodium persulfate was added. Over the next 3 hours, 1.12 g (0.028 raol) of NaOH was added to this solution in small portions with stirring. The resulting mixture was stirred overnight. The excess of oxidiser was neutralised with sodium sulphite. The mixture was acidified by HCl to pH 2. The product was extracted with EtOAc (100 ml), washed with water, brine and dried (MgSO 4 ). The compound was purified by CC on silica gel (eluent: chloroform). Yield: 1.42 g (84%). MALDI-TOF, positive mode: 262.978 (MI + Na; 43%). EXAMPLE 4 (S)-6-amino-6,6-dideutero-2-(/erf-butoxycarbonylamino)-hexan oic acid (5)
100321 Method 1. To a solution of 100 mg (0.41 mmol) of nitrile (4) in 2 ml of AcOD (98% isotopic purity), 15 mg (15 mass-%) of PtO 2 was added. The mixture was stirred in the atmosphere of D 2 (98% isotope purity) at rt for 3 hours, filtered, and evaporated at reduced pressure. The residue was purified (CC, silica; eluent: chloroform-MeOH-AcOH). Yield: 65 mg (63%) as oil. Isotope purity was determined to be about 90% judging by the NMR signal ratio (2.7 md and 3.6 md; the ratio is 2:1 for Lys, but D 2 -LyS should not have a signal at 2.7 md).
[00331 Method 2. To a solution of nitrile (4) (1.5 g, 6.2 mmol) in 30 ml of AcOD (97% isotopic purity), 242 mg (15 mass-%) of PtO 2 was added. Reaction mixture was stirred in the atmosphere of D 2 (97% isotope purity) at rt for 20 hours, filtered, and evaporated at reduced pressure. The residue was purified (CC, silica; eluent: chloroform-MeOH-AcOH). Yield: 1.2 g (79%) as oil. Isotope purity was determined to be >85% judging by the NMR signal ratio (See Method 1). EXAMPLE 5 (S)-2,6-diamino-6,6-dideuterohexanoic acid (6)
|0034] To a solution of 1.2 g (4.88 mol) of deuterated Boc-Lys (5) in EtOH (5 ml), concentrated HCl (2 ml) was added. The reaction mixture was warmed up to 5O 0 C,
stirred for 30 min., and the solvent was removed in vacuo. The residue was dissolved in 20 ml EtOH, brought to a boil, and 0.5 g (6.3 mmol) of Py was added dropwise. The mixture was cooled down and left at + 4 0 C overnight. Yield: 0.33 g (37%; after drying) of product as white crystals. MALDI-TOF, positive mode: 149.286 (MI + H; 73%). EXAMPLE 6 Expression, purification and folding of recombinant LOX.
[0035] Mouse LOX cDNA corresponding to the processed enzyme (amino acid coordinates 163-411) was amplified by RT-PCR using mouse heart total RNA and a proofreading DNA polymerase. The PCR product was cloned into pQE30 expression (Qiagen, Valencia, CA) vector at BamH I site. The expression was induced by addition to the log-phase E. coli cells of 1 mM IPTG and incubation for 4 h at 37°C. The cells were lysed in a 6M urea buffer, cleared by centrifugation and incubated with NTA-Ni 2+ -Agarose (Qiagen, Valencia, CA). The agarose was thoroughly washed with 6M urea and the bound protein eluted with imidazole in 6M urea. For refolding, the dialysis protocol described by [Jung ST et a!., Protein Exper Purif. 2003; 37:240-246] was used, but the starting concentration of N-lauroylsarcosine was increased and an additional dialysis step against glutathione was included to assist correct folding. EXAMPLE 7 Functional non-radioactive assay of LOX enzymatic activity.
[0036] A non-radioactive cross-linking assay was developed that allows detection of oxidized lysine residues on solid support using reaction with a biotinylation reagent and an enzyme assay. Collagen from cold-water fish was immobilized on EIA plates (Costar), briefly incubated with hydroxylamine, thoroughly washed and incubated with the recombinant LOX in a phosphate buffer with free access to air as a source of oxygen. This was followed by washing, reaction with biotin hydrazide, ExtrAvidin-peroxidase and development with orthophenylenediamine. γ-aminopropionitrile was used as an inhibitor of LOX whenever necessary.