Studies on α₂-Plasmin Inhibitor Fragment T-11. III. Structure-Activity Relationships among the Fragments of T-11, the Plasminogen Binding Site (s) of Human α₂-Plasmin Inhibitor

抄録

Twelve shortened fragments of peptide T-11, which is a part of human α₂-plasmin inhibitor and contains its plasmin (ogen) -binding site (s) were synthesized by a conventional solution method. The dissociation constants for the interaction between these synthetic fragments and plasmin were determined. Among these fragments, the octadecapeptide containing C-terminal lysine of T-11, which consists of 26 amino acids, was found to be the smallest active fragment of T-11. The N-terminal and the central portion fragments of T-11 possessed no binding activity. The heptadecapeptide which has the same sequence as the octadecapeptide but lacks the C-terminal lysine showed no binding activity. The hexadecapeptide containing the C-terminal lysine but lacking the 10th lysine in T-11 scarcely exhibited the activity. Thus, the lysine residues at positions 10 and 26 in T-11 must be important for the activity.