Involvement of aspartic and glutamic residues in kringle-2 of tissue-type plasminogen activator in lysine binding, fibrin binding and stimulation of activity as revealed by chemical modification and oligonucleotide-directed mutagenesis

In this paper it is shown by chemical modification experiments that one or more glutamic acid or aspartic acid residues in K 2 of t-PA are involved in the interaction with fibrin and lysine analogs and in stimulation of activity by fibrinogen fragments. The role of the five different ASP and GLU residues present in K 2 of t-PA in lysine binding, fibrin binding and stimulation of activity has been investigated by construction of mutant t-PA molecules in which one or two specific ASP or GLU residues were changed to ASN and GLN residues respectively by means of oligonucleotide-directed mutagenesis of the t-PA cDNA followed by expression in CHO cells.