PURPOSE: To obtain the subject new stabilized derivative free from side effect such as hemorrhage and useful as a thrombolytic agent, etc., by substituting asparagin of a human urokinase precursor at a specific position counted from the N-terminal with an amino acid other than glutamine.
CONSTITUTION: An mRNA extracted from human kidney cell by conventional process is used as a template to synthesize a cDNA. A cDNA library prepared from the cDNA is cloned to prepare a DNA coding a human urokinase precursor and a single-stranded DNA is prepared from the DNA. A DNA oligomer for introducing a mutation to substitute the 407th asparagine counted from the N-terminal with an amino acid other than glutamine is introduced by a site-specific mutation to obtain a DNA coding a variant human urokinase precursor. The DNA is bound to a manifestation vector and introduced into a host cell. The obtained transformant is cultivated to effect the manifestation of gene and obtain the objective urokinase precursor having substituted asparagine at 407th site counted from the N-terminal.
HONMA NOBUYUKI
YAMADA MASAYUKI
