Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.22.32 (bromelain)
 1,025 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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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PMID:Comparison of the size and physical properties of gamma-glutamyltranspeptidase purified from rat kidney following solubilization with papain or with Triton X-100. 1 82

Two different types of gamma-glutamyltranspeptidase (gamma-GTP) have been found in normal human pancreas following bromelain treatment. On the other hand, three human pancreatic ductal cell carcinomas have only a single type of gamma-GTP upon analysis with polyacrylamide gel electrophoresis, anion-exchange column chromatography and isoelectric focusing. Carcinoma gamma-GTPs were almost identical to one of the two types of normal pancreatic gamma-GTPs. The gamma-GTP from pancreatic carcinomas bound to anion-exchange column and was eluted at the same NaCl fractions as normal pancreatic gamma-GTP. The properties of pancreatic carcinoma-gamma-GTP, as assessed by binding to concanavalin A and lentil lectin affinity columns, were also similar to one of the two enzymes of normal pancreas. No apparent difference in isoelectric points was found between the carcinoma gamma-GTPs and one of the two normal pancreatic gamma-GTPs.
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PMID:Characterization of gamma-glutamyltranspeptidase from human exocrine pancreatic carcinomas. 286 14

By digestion of detergent-solubilized gamma-glutamyltransferase (GGT), isolated from bovine kidney with bromelain, the liberation of 4 protein fragments was demonstrated. The fragment migrating most quickly in gel electrophoresis showed gamma-glutamyltranspeptidase activity and the most slowly migrating fragment showed peptidase activity. Protease-solubilized GGT is a sialoprotein with a molecular weight of 95,000. After treatment with sodium dodecylsulfate it was separated into two unequal subunits with molecular weights of 26,000 and 69,000. Sugar components were found only in the heavy subunit. Some catalytic differences were found between the two solubilized GGT forms. The immunoprecipitate obtained from detergent-solubilized GGT retained about 50% of the initial enzyme activity. The enzyme is inactivated with phenylmethanesulfonyl fluoride in the presence of maleate and with 6-diazo-5-oxo-L-norleucine.
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PMID:Bovine kidney gamma-glutamyltransferase. Solubilized forms, biochemical and immunochemical properties. 615 97