each of four genetically engineered variants ( one variant with growth factor and kringle 1 domains deleted and kringle 2 duplicated , a second variant with a cysteine for arg substitution in the growth factor domain , a third variant with an additional urokinase kringle inserted , and a fourth variant with the growth factor domain deleted ) and enzymatically deglycosylated t-pa exhibited prolonged half-life after bolus intravenous injection in rabbits .
C0042071
urokinase
C0064417
kringle