Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P17174 (aspartate aminotransferase)
 14,872 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Macromolecular aspartate aminotransferase (L-aspartate: 2-oxoglutarate aminotransferase EC 2.6.1.1, AST) was found in the serum of a patient with benign hypertension. The serum total AST and mitochondrial AST (mAST) activities were proportionately higher. The abnormal AST was found to be a macromolecular complex composed of mAST and immunoglobulin G of the kappa-lambda type. The dissociated IgG from the complex was shown to combine with human and rat mAST, but not with cytosolic AST of both species. Molecular mass of the macromolecular AST was estimated to be 360,000 Da. These results indicate that the complex may consist of one IgG molecule associated with two mAST molecules. By the method of papain digestion the binding site of immunoglobulin in the complex appeared to be located in the Fab portion of the IgG molecule. This finding strongly suggests that the AST-immunoglobulin complex is a specific antigen-antibody complex.
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PMID:Mitochondrial aspartate aminotransferase linked to immunoglobulin G of the kappa-lambda type: report of a case. 309 51

Sodium boro[3H]hydride treatment of holoaspartate aminotransferase results in the reduction of the Schiff's base formed between pyridoxal phosphate and Lys 258. Treatment of the reduced enzyme with papain followed by acid hydrolysis liberates epsilon-N-[3H]pyridoxyl lysine which is degraded to [3H]pyridoxamine diHCl and stereochemically analyzed with apoaspartate aminotransferase. Sodium boro[3H]hydride treatment of active site carbamylated aspartate aminotransferase reconstituted with pyridoxyl phosphate and sodium aspartate results in the trapping of an enzyme x substrate complex through the reduction of the Schiff's base formed between pyridoxal phosphate and aspartate. Active site bound N-[3H]pyridoxyl aspartate is liberated by treatment with papain and degraded to [3H]pyridoxamine diHCl for stereochemical analysis. Borohydride reduction of the holoenzyme occurs from the re face of the pyridoxal phosphate Lys 258 Schiff's base. Similarly, reduction of active site carbamylated enzyme x substrate complex occurs from the re face of the pyridoxal phosphate-aspartate Schiff's base. These results indicate that when active site carbamylated enzyme binds substrate to pyridoxal phosphate it does so stereospecifically and without changing the face of the Schiff base that is available for reduction as compared to native enzyme.
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PMID:Stereospecificity of sodium borohydride reduction of Schiff bases at the active site of aspartate aminotransferase. 741 Mar 85

Buffalo skim milk retentate was hydrolyzed with papain for 4 h (enzyme:substrate, 1:200), resulting in a retentate hydrolysate (RH) with a degree of hydrolysis of 23%. We then investigated the potential hepatoprotective activity of RH at 250 and 500 mg/kg of body weight per day on carbon tetrachloride (CCl4)-induced oxidative stress in albino rats. Liver biomarkers (alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and lactate dehydrogenase), kidney biomarkers (urea, creatinine), and serum lipid profile (total lipids and triglycerides) were measured, in addition to histopathological status. Injection of CCl4 significantly increased all liver and kidney biomarkers compared with the negative control. In contrast, CCl4 injection significantly reduced hepatic antioxidant enzyme activities; that is, glutathione peroxidase and superoxide dismutase. Oral administration of RH for 28 d effectively maintained a physiologically normal range of liver and kidney biomarkers compared with the positive control. Furthermore, RH administration significantly increased activities of glutathione peroxidase and superoxide dismutase. Histopathological sections of CCl4-stressed rats treated with RH were different from that of the positive control and were similar to those of the negative control, in a concentration-dependent manner. Our results demonstrated the antihepatotoxic activities of buffalo milk RH and demonstrated that the higher RH concentration (500 mg/kg of body weight per day) could maintain the healthy biological status of the CCl4-injected rats.
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PMID:Hepatoprotective action of papain-hydrolyzed buffalo milk protein on carbon tetrachloride oxidative stressed albino rats. 3183 90