First Author | Miyata T | Year | 1982 |
Journal | Proc Natl Acad Sci U S A | Volume | 79 |
Issue | 20 | Pages | 6132-6 |
PubMed ID | 6216475 | Mgi Jnum | J:47228 |
Mgi Id | MGI:1271053 | Doi | 10.1073/pnas.79.20.6132 |
Citation | Miyata T, et al. (1982) Plasminogen Tochigi: inactive plasmin resulting from replacement of alanine-600 by threonine in the active site. Proc Natl Acad Sci U S A 79(20):6132-6 |
abstractText | Structural studies on a hereditarily abnormal plasminogen, plasminogen Tochigi, have been performed to identify the difference responsible for its lack of proteolytic activity. The plasminogen sample used was from a heterozygote and thus consisted of apparently equal amounts of normal and defective plasminogen molecules. Amino acid sequence analysis of a tryptic peptide isolated from the abnormal plasminogen indicated that Ala-600 (equivalent to Ala-55 in the chymotrypsin numbering system) had been replaced by Thr. No other substitutions in the active-site residues--namely, His-57, Asp-102, and Ser-195--were found. Molecular models for chymotrypsin and the bovine trypsin-pancreatic trypsin inhibitor complex indicate that Ala-55 is very near the active-site His. The Thr at position 55 in plasminogen (plasmin) Tochigi may perturb His-57 such that the proton transfers associated with the normal catalytic process cannot occur in the abnormal plasmin. |