Linked Life Data

7698320

Source:http://linkedlifedata.com/resource/pubmed/id/7698320

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2-3
pubmed:dateCreated
1995-5-1
pubmed:abstractText
Temporary inhibition of the cysteine proteinases papain and cathepsin L was observed with several hairpin loop mutants of recombinant chicken cystatin at enzyme concentrations above nanomolar. Kinetic modelling of inhibition data, gel electrophoresis and amino acid sequencing revealed that reappearance of papain activity is due to selective cleavage of the Gly(9)-Ala10 bond in the N-terminal binding area of the chicken cystatin variants, resulting in truncated inhibitors of lower affinity. Cleavage of the same bond by contaminating papaya proteinase IV was ruled out by previous purification of papain and suitable control experiments. According to the proposed kinetic model, cleavage occurs within the enzyme-inhibitor complex with first order rate constants ktemp of 2.3 x 10(-3) up to 5 x 10(-1) s-1. A similar ktemp/Km ratio was found for all mutants (0.7 x 10(6)-2.1 x 10(6) s-1.M-1); it is almost identical with the kcat/Km ratio of the peptide substrate Z-Phe-Arg-NHMec. These results suggest that distorted contacts of one of the hairpin loops affect binding of the N-terminal contact area in a way that covalent interaction of the Gly(9)-Ala10 bond with the active-site Cys residue of papain can occur and the bond is cleaved in a substrate-like manner.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0014-5793
pubmed:author
pubmed:issnType
Print
pubmed:day
20
pubmed:volume
361
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
185-90
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Temporary inhibition of papain by hairpin loop mutants of chicken cystatin. Distorted binding of the loops results in cleavage of the Gly(9)-Ala10 bond.
pubmed:affiliation
Institut für Physiologische Chemie, Physikalische Biochemie und Zellbiologie der LMU München, Germany.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't