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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
21
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pubmed:dateCreated |
1991-8-23
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pubmed:databankReference |
http://linkedlifedata.com/resource/pubmed/xref/GENBANK/M63255,
http://linkedlifedata.com/resource/pubmed/xref/GENBANK/M63832,
http://linkedlifedata.com/resource/pubmed/xref/GENBANK/M63833,
http://linkedlifedata.com/resource/pubmed/xref/GENBANK/M63834,
http://linkedlifedata.com/resource/pubmed/xref/GENBANK/M63835,
http://linkedlifedata.com/resource/pubmed/xref/GENBANK/M63926,
http://linkedlifedata.com/resource/pubmed/xref/GENBANK/M63977,
http://linkedlifedata.com/resource/pubmed/xref/GENBANK/M63978,
http://linkedlifedata.com/resource/pubmed/xref/GENBANK/M64288,
http://linkedlifedata.com/resource/pubmed/xref/GENBANK/M64620
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pubmed:abstractText |
Expression of lysosomal cysteine proteinases was studied during fetal calf myoblast-myotube differentiation. Activities of cathepsin B and L, but not cathepsin H, increase during bovine myogenic differentiation. In fetal muscle, cathepsin B and L activities are 2-4-fold orders of magnitude lower than in cultured myoblasts. Active-site titrations of cathepsin B with E-64 nevertheless reveal similar concentrations of active cathepsin B in myoblasts and myotubes, but 5-6-fold lower concentrations in fetal muscle. To specify whether concentrations of cathepsin B are related to levels of cathepsin B transcript, a cDNA clone encoding bovine cathepsin B was isolated and liquid hybridizations were performed with 32P-riboprobes complementary to the mRNA. In agreement with active-site titrations, there is no difference in cathepsin B mRNA levels between cultured myoblasts and myotubes, but lower levels of mRNA are found in fetal muscle. Concentrations of active cathepsin B therefore reflect levels of cathepsin B mRNA. Kinetic studies revealed that the catalytic efficiency (kcat/Km) of cathepsin B is 2-3-fold higher in myotubes than in myoblasts. The increase in cathepsin B activity during calf myoblast-myotube differentiation is thus due to modifications of enzymatic properties, and not of enzyme concentrations. The different catalytic efficiency of cathepsin B in myotubes and myoblasts was related neither to modifications of mRNA size, as revealed by Northern blot analysis, nor to a different Mr of the active enzyme, as revealed by affinity labeling with benzyloxycarbonyl-Tyr(-125I)-Ala-CHN2, but to limited differences in cathepsin B isozymes.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
Jul
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pubmed:issn |
0021-9258
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
25
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pubmed:volume |
266
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
14104-12
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pubmed:dateRevised |
2003-11-14
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pubmed:meshHeading |
pubmed-meshheading:1856234-Affinity Labels,
pubmed-meshheading:1856234-Amino Acid Sequence,
pubmed-meshheading:1856234-Animals,
pubmed-meshheading:1856234-Base Sequence,
pubmed-meshheading:1856234-Blotting, Northern,
pubmed-meshheading:1856234-Cathepsin B,
pubmed-meshheading:1856234-Cattle,
pubmed-meshheading:1856234-Cell Differentiation,
pubmed-meshheading:1856234-Cloning, Molecular,
pubmed-meshheading:1856234-DNA,
pubmed-meshheading:1856234-Gene Expression,
pubmed-meshheading:1856234-Isoelectric Focusing,
pubmed-meshheading:1856234-Kinetics,
pubmed-meshheading:1856234-Lysosomes,
pubmed-meshheading:1856234-Molecular Sequence Data,
pubmed-meshheading:1856234-Muscles,
pubmed-meshheading:1856234-RNA, Messenger,
pubmed-meshheading:1856234-Restriction Mapping
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pubmed:year |
1991
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pubmed:articleTitle |
Expression of lysosomal cathepsin B during calf myoblast-myotube differentiation. Characterization of a cDNA encoding bovine cathepsin B.
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pubmed:affiliation |
Unité de Recherches sur l'Expression des Protéases, SRV Theix, Institut National de la Recherche Agronomique, Ceyrat, France.
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pubmed:publicationType |
Journal Article
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