Linked Life Data

15110990

Source:http://linkedlifedata.com/resource/pubmed/id/15110990

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2-3
pubmed:dateCreated
2004-4-27
pubmed:abstractText
Although the biochemical changes that occur during autolysis of mu- and m-calpain are well characterized, there have been few studies on properties of the autolyzed calpain molecules themselves. The present study shows that both autolyzed mu- and m-calpain lose 50-55% of their proteolytic activity within 5 min during incubation at pH 7.5 in 300 mM or higher salt and at a slower rate in 100 mM salt. This loss of activity is not reversed by dialysis for 18 h against a low-ionic-strength buffer at pH 7.5. Proteolytic activity of the unautolyzed calpains is not affected by incubation for 45 min at ionic strengths up to 1000 mM. Size-exclusion chromatography shows that ionic strengths of 100 mM or above cause dissociation of the two subunits of autolyzed calpains and that the dissociated large subunits (76- or 78-kDa) aggregate to form dimers and trimers, which are proteolytically inactive. Hence, instability of autolyzed calpains is due to aggregation of dissociated heavy chains. Autolysis removes the N-terminal 19 (m-calpain) or 27 (mu-calpain) amino acids from the large subunit and approximately 90 amino acids from the N-terminus of the small subunit. These regions form contacts between the two subunits in unautolyzed calpains, and their removal leaves only contacts between domain IV in the large subunit and domain VI in the small subunit. Although many of these contacts are hydrophobic in nature, ionic-strength-induced dissociation of the two subunits in the autolyzed calpains indicates that salt bridges have an important, possibly indirect, role in the domain IV/domain VI interaction.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0006-3002
pubmed:author
pubmed:issnType
Print
pubmed:day
3
pubmed:volume
1691
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
91-103
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Effects of autolysis on properties of mu- and m-calpain.
pubmed:affiliation
Muscle Biology Group, University of Arizona, Tucson, AZ 85721-0038, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't