Cucurbita maxima trypsin inhibitor-V (CMTI-V) is also a specific inhibitor of human blood coagulation factor β-factor XIIa. A recombinant version of CMTI-V has allowed probing of roles of individual amino acid residues including the reactive site residue, lysine (P1), by site-directed mutagenesis. The K44R showed at least a 5-fold increase in inhibitory activity toward human β-factor XIIa, while there was no change toward bovine trypsin. This result demonstrates that β-factor-XIIa prefers an arginine residue over lysine residue, while trypsin is non-specific to lysine or arginine in its binding pocket. On the other hand, the specificity of CMTI-V could be changed from trypsin to chymotrypsin inhibition by mutation of the P1 residue to either leucine or methionine (K44L or K44M).
|Number of pages||6|
|Journal||Biochemical and Biophysical Research Communications|
|Publication status||Published - 1995 Feb 27|
All Science Journal Classification (ASJC) codes
- Molecular Biology
- Cell Biology