Document Detail


Acid-activatable cysteine proteinases in the cellular slime mold Dictyostelium discoideum.
MedLine Citation:
PMID:  8662904     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Studies of the cysteine proteinases of the cellular slime mold Dictyostelium discoideum have been aided by a simple acid treatment step that was incorporated into the standard one-dimensional gelatin-sodium dodecyl sulfate-polyacrylamide gel electrophoresis assay procedure. The step involved immersing the separating gel in 10% (v/v) glacial acetic acid for 30-60 s immediately after electrophoresis. This modified approach revealed the presence of acid-activatable forms of some enzymes with noticeable increases in their ability to hydrolyze gelatin, a substrate present in the sodium dodecyl sulfate-polyacrylamide gels, and peptidyl amidomethylcoumarins. The activation has been analyzed using extracts of dormant spores from which cysteine proteinase activity had previously appeared low or virtually absent. The major acid-activatable proteinase had an apparent molecular mass of 48 kDa. Its activation was not due to autocatalysis as it was not prevented by mercuric chloride, an inhibitor of the enzyme, and was not accompanied by a significant change in electrophoretic mobility. It was most likely due to a conformational change and/or the removal of a low molecular weight inhibitor. The acid treatment has also revealed the presence of acid-activatable cysteine proteinases in vegetative cells, in which cysteine proteinase activity is present at high levels, as well as among enzymes from the developmental cells which have much lower cysteine proteinase activity. Indeed novel developmental forms were detected at some stages. These results provide additional insight concerning cysteine proteinase expression at various stages during development in the slime molds. A developmental model is presented which suggests that the crypticity of the cysteine proteinases in dormant spores may be governed by proton pumps and endogenous lysosomotropic agents.
Authors:
M J North; K Nicol; T W Sands; D A Cotter
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  271     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  1996 Jun 
Date Detail:
Created Date:  1996-08-20     Completed Date:  1996-08-20     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  14462-7     Citation Subset:  IM    
Affiliation:
Department of Biological and Molecular Sciences, the University of Stirling, Stirling FK9 4LA, Scotland.
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MeSH Terms
Descriptor/Qualifier:
Acetic Acid
Acetic Acids
Amino Acid Sequence
Animals
Cysteine Endopeptidases / isolation & purification*,  metabolism*
Dictyostelium / enzymology*,  growth & development
Electrophoresis, Polyacrylamide Gel / methods
Enzyme Activation
Hydrogen-Ion Concentration
Molecular Sequence Data
Protein Conformation
Substrate Specificity
Chemical
Reg. No./Substance:
0/Acetic Acids; 64-19-7/Acetic Acid; EC 3.4.22.-/Cysteine Endopeptidases

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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