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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
24
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pubmed:dateCreated |
1977-2-16
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pubmed:abstractText |
gamma-Glutamyltranspeptidase is associated with the brush border membrane of kidney proximal straight tubule cells. It can be solubilized qualitatively by treatment with papain or Triton X-100. Neither procedure affects its catalytic activity but the two resulting forms of the enzyme differ considerably in their physical properties. The papain-solubilized transpeptidase is soluble in aqueous buffers and was purified 430-fold. It has an s20,w of 4.9 S, a Stokes radius of 36 A, and a calculated molecular weight of 69,000. It appears homogeneous by sedimentation equilibrium centrifugation (Mr=66,700). In contrast, the Triton-solubilized transpeptidase is soluble only in the presence of detergents and was purifed 300-fold. This form of the enzyme has a Stokes radius of 70 A but an s20,w of only 4.15 S. Aggregation of the enzyme just below the critical micelle concentration of Triton X-100 and its ability to bind 1.16 mg of Triton X-100-protein complex was calculated to be 169,000, but the glycoprotein portion of the complex is 52% of the total mass (87,000). The mass of Triton X-100 (82,000) is consistent with its reported micelle molecular weight. Treatment of the Triton-purified transpeptidase with papain or bromelain results in a form of the enzyme identical in all respects with the papain-purified enzyme. Both the Triton- and papain-purified transpeptidase exhibit two protein bands on sodium lauryl sulfate-polyacrylamide gel electrophoresis. The smaller subunits of the two forms appear identical (Mr=27,000), while the larger subunits of the Triton- and papain-purified enzyme have apparent molecular weights of 54,000 and 51,000, respectively. These data suggest that a peptide (3,000 to 19,000) in the larger subunit of gamma-glutamyltranspeptidase is responsible for its binding to Triton micelles and probably for holding the enzyme in the brush border membrane.
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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 |
Dec
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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 |
251
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
8763-70
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pubmed:dateRevised |
2006-11-15
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pubmed:meshHeading |
pubmed-meshheading:12182-Animals,
pubmed-meshheading:12182-Kidney,
pubmed-meshheading:12182-Male,
pubmed-meshheading:12182-Microsomes,
pubmed-meshheading:12182-Molecular Weight,
pubmed-meshheading:12182-Papain,
pubmed-meshheading:12182-Polyethylene Glycols,
pubmed-meshheading:12182-Protein Conformation,
pubmed-meshheading:12182-Rats,
pubmed-meshheading:12182-Solubility,
pubmed-meshheading:12182-gamma-Glutamyltransferase
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pubmed:year |
1976
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pubmed:articleTitle |
Comparison of the size and physical properties of gamma-glutamyltranspeptidase purified from rat kidney following solubilization with papain or with Triton X-100.
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pubmed:publicationType |
Journal Article,
Comparative Study
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