Amino acid analysis of human von Willebrand factor fragments cleaved by porcine calpain II.
Porcine calpain II (Ca2+-dependent cysteine proteinase) was found to cleave human von Willebrand Factor (HvWF) into two major fragments (approximately 165 kDa and 145 kDa) in sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis (PAGE). But, the cleavage was not complete even with a high enzyme/substrate ratio (w/w) of 1:10 for 20 hours. The two main fragments were isolated by electroelution, and the amino-terminal sequences as well as amino acid compositions were determined. Amino acid compositions of these two fragments were similar to those of equivalent parts of whole HvWF. The amino-terminal sequence of the 165 kDa fragment was SLSCRPPMVK corresponding to the amino-terminal residues of whole HvWF amino acid sequence which was recently determined by Titani et al. (Biochemistry 25:3171-84, 1986). The amino-terminal sequence of the 145 kDa fragment was SHRVNCDRGL beginning from 1151th amino acid of whole HvWF.
Nozaki
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Department of Internal Medicine, School of Medicine, Tokai University, Kanagawa, Japan.
D000596:Amino Acids / Q000032:analysis*; D000818:Animals; D002154:Calpain / Q000378:metabolism*; D006801:Humans; D008970:Molecular Weight; D010446:Peptide Fragments / Q000032:analysis*; D013552:Swine; D014841:von Willebrand Factor / Q000032:analysis*
D000596:Amino Acids; D010446:Peptide Fragments; D014841:von Willebrand Factor; D002154:Calpain