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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
13
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pubmed:dateCreated |
1982-10-21
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pubmed:abstractText |
Linear maltooligosaccharides, e.g., maltoheptaose or terminal 4-O-methylmaltoheptaose, activated by cyanogen bromide, react covalently with rabbit muscle phosphorylases b and a (EC 2.4.1.1). Site-specific modification prevents further binding to glycogen and shifts the phosphorylase a tetramer-dimer equilibrium in favor of the dimer. Use was made of these properties to separate by affinity chromatography and gel filtration phosphorylase a dimers with specifically bound oligosaccharide from unspecifically modified products. The phosphorylase a-maltoheptaose derivative carries one oligosaccharide residue per monomer and can be distinguished from the native enzyme by its electrophoretic mobility in polyacrylamide gels or by affinity electrophoresis. Phosphorylase a preparations with covalently bound maltooligosaccharides are enzymatically active in the presence of a primer and alpha-D-glucopyranose 1-phosphate (glucose-1-P). Methylation of the nonreducing chain terminus of the bound oligosaccharide has no effect on glycogen synthesis. These findings exclude the participation of bound oligosaccharides in chain elongation. Purified covalent phosphorylase a-maltoheptaose complexes are stable dimers. They are no longer activated by glycogen. The properties of covalently modified phosphorylase-oligosaccharides are consistent with and provide direct evidence for the existence of a glycogen storage site in rabbit muscle phosphorylases. Covalent occupation of the storage site renders the affinity of glucose-1-P to phosphorylase a independent of modulation by glycogen, supporting the assumption that the glycogen storage site is involved in interactions with the catalytic site.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Oligosaccharides,
http://linkedlifedata.com/resource/pubmed/chemical/Phosphorylase a,
http://linkedlifedata.com/resource/pubmed/chemical/Phosphorylase b,
http://linkedlifedata.com/resource/pubmed/chemical/Phosphorylases,
http://linkedlifedata.com/resource/pubmed/chemical/maltooligosaccharides
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pubmed:status |
MEDLINE
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pubmed:month |
Jun
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pubmed:issn |
0006-2960
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
22
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pubmed:volume |
21
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
3043-50
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pubmed:dateRevised |
2006-11-15
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pubmed:meshHeading |
pubmed-meshheading:6809045-Animals,
pubmed-meshheading:6809045-Binding Sites,
pubmed-meshheading:6809045-Crystallization,
pubmed-meshheading:6809045-Kinetics,
pubmed-meshheading:6809045-Muscles,
pubmed-meshheading:6809045-Oligosaccharides,
pubmed-meshheading:6809045-Phosphorylase a,
pubmed-meshheading:6809045-Phosphorylase b,
pubmed-meshheading:6809045-Phosphorylases,
pubmed-meshheading:6809045-Rabbits
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pubmed:year |
1982
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pubmed:articleTitle |
Rabbit muscle phosphorylase derivatives with oligosaccharides covalently bound to the glycogen storage site.
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pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
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