Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.6.1.2 (alanine aminotransferase)
 26,722 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Diversion of portal blood in congenital portosystemic shunts (CPSS) results in liver atrophy and passage of toxins into the systemic circulation causing hepatic encephalopathy. In some dogs, there is indirect evidence for hepatic insufficiency, but histologic findings are equivocal. This study determined whether hepatocyte integrity in PSS is comprised at a subcellular level using analytical subcellular fractionation of liver biopsies. Six dogs with CPSS had hypoproteinemia (6/6), increased serum alkaline phosphatase (6/6) and alanine aminotransferase (4/6) activity, hypocholesterolemia (6/6), and decreased blood urea (2/6). Liver biopsy specimens had increased activities (mU/mg protein) of alkaline phosphatase (17.9 +/- 10.1; controls 5.1 +/- 5.3: P less than 0.01), but not of other plasma membrane enzymes. There were increased activities of endoplasmic reticular (neutral alpha-glucosidase: 1.67 +/- 0.7; controls 0.86 +/- 0.2: P less than 0.01) and lysosomal enzymes (N-acetyl-beta-glucosaminidase: 12.6 +/- 2.3; controls 6.24 +/- 2.7: P less than 0.01; alpha-mannosidase: 0.85 +/- 0.5; controls 0.39 +/- 0.3: P less than 0.05). Subcellular fractionation on reorientating sucrose density gradients showed a high-density peak of alkaline phosphatase suggestive of a specific increase in the biliary canalicular component of enzyme activity. Neutral alpha-glucosidase was shifted to denser fractions, indicative of an increase in the proportion of rough-to-smooth endoplasmic reticulum and consistent with enhanced synthesis of membranous enzymes. There was also evidence for increased fragility of intracellular organelles, particularly lysosomes. In contrast, histology showed either no abnormalities or minor degenerative changes compatible with hepatic underperfusion.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Hepatic organelle pathology in dogs with congenital portosystemic shunts. 161 98

Bloodstream forms of Trypanosoma brucei have been screened for the presence of enzymes that could serve as markers for the plasma membrane, flagellar pocket, lysosomes, endoplasmic reticulum and Golgi apparatus in order to study the subcellular organization of the digestive system of the parasite. Acetylesterase, acid DNase, acid phosphatase, acid phosphodiesterase, acid proteinase, acid RNase, alanine aminotransferase, galactosyl transferase, alpha-glucosidase, inosine diphosphatase and alpha-mannosidase were partially characterized and their assays optimized for pH-dependent activity, linearity of reaction with respect to incubation time and enzyme concentration, and the effect of inhibitors and activators. The association of these enzymes with particulate material and the presence of structural latency were investigated. Acid proteinase and alpha-mannosidase are particle-bound and latent in cytoplasmic extracts; they can be activated and solubilized in part by Triton X-100. Similar results were obtained for acid phosphatase, acid phosphodiesterase and inosine diphosphatase. Neutral alpha-glucosidase, though partly sedimentable, does not show latency and is readily solubilized by the detergent. Galactosyl transferase is firmly membrane-bound even in the presence of 0.1% Triton X-100. Cell fractionation by differential centrifugation and density equilibration on sucrose gradients revealed that both alpha-mannosidase and acid proteinase are associated with organelles that band at a density of about 1.20 g/cm3. Inosine diphosphatase, galactosyl transferase, acid phosphatase and acid phosphodiesterase sediment predominantly as microsomal constituents equilibrating at densities between 1.13 and 1.15 g/cm3. In addition, inosine diphosphatase and galactosyl transferase exhibit considerable activity at higher densities (1.18-1.25 g/cm3). Neutral alpha-glucosidase is mainly recovered in the nuclear and microsomal fraction; its particulate part equilibrates as a single band at rho = 1.22 g/cm3. Acetylesterase and acid DNase are largely soluble, whereas acid RNase does not produce distinct sedimentation and banding profiles. In intact cells, neutral alpha-glucosidase and acid phosphatase appear to be highly accessible to their substrates. It is tentatively concluded that (a) acid proteinase and alpha-mannosidase are lysosomal enzymes, (b) acid phosphatase and acid phosphodiesterase are associated with the flagellar pocket and part of the former enzyme probably with the endoplasmic reticulum, (c) galactosyl transferase is a constituent of the Golgi apparatus, and (d) alpha-glucosidase may serve as a marker for the plasma membrane. Inosine diphosphatase may also be derived from the latter structure.
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PMID:Subcellular fractionation of Trypanosoma brucei bloodstream forms with special reference to hydrolases. 624 76

Homogenates of liver from cases of hepatic cirrhosis due to alpha 1-antitrypsin deficiency (PiZZ) alcoholism were analyzed for their content of various lysosomal enzymes. Also determined were the specific activities of lactate dehydrogenase, glutamate-oxaloacetate transaminase, glutamate-pyruvate transaminase, and creatine phosphokinase in the extracts of liver from cases of both kinds of hepatic cirrhosis: all of these activities were within the range of control values. Similarly, the specific activities of the following lysosomal hydrolases were unremarkable: acid phosphatase, beta-mannosidase, beta-fucosidase, beta-glucuronidase and beta-glucosidase. Hexosaminidase specific activity was increased twofold in livers from the cases of cirrhosis due to alpha 1-antitrypsin deficiency. The specific activity of alpha-mannosidase (measured at pH 4.5) in homogenates of livers from PiZZ individuals with cirrhosis and those with alcoholic cirrhosis was increased two- to four-fold. Chromatography of the high-speed supernatant fraction from homogenates of livers of cirrhotic and noncirrhotic individuals on columns of DEAE-cellulose resolved alpha-mannosidase activity into two components: under the conditions employed, acid pH optimum (pH 4.5) alpha-mannosidase did not bind to the resin, whereas intermediate pH optimum (pH 5.5) alpha-mannosidase could be eluted with 0.1 mol/l NaCl. Liver from one case of (PiZZ) alpha 1-antitrypsin deficiency and emphysema, without demonstrable cirrhosis, was found to contain normal levels of both acid alpha-mannosidase and intermediate alpha-mannosidase. However, cases of cirrhosis due to alpha 1-antitrypsin deficiency contained twice as much acid alpha-mannosidase and only one third to one fourth as much intermediate alpha-mannosidase as controls. The deficiency in hepatic intermediate alpha-mannosidase was also observed in 5 of 5 cases of alcoholic cirrhosis.
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PMID:Altered alpha-mannosidase isoenzymes in the liver in hepatic cirrhosis. 697 51

The purpose of the study was to develop a procedure for predicting a relapse of herpetic keratitis in children, by taking into account the results of tear biochemical analysis. The tears from 47 children with herpetic keratitis were examined for the levels of total protein, the concentration of acute-phase proteins, such as orosomucoid and C-reactive protein, the activities of transferases: gamma-glutamyltranspeptidase transferase, aspartate aminotransferase, and alanine aminotransferase, those of lysosomal glycosidases: alpha-mannosidase, beta-glycosidase, and beta-glucuronidase. Tear biochemical assay made it possible to evaluate the efficiency of treatment and to develop a procedure for predicting a recurrence of herpetic keratitis in children. Determination of the tear activity of the glycosidases may be used to predict recurrent herpetic keratitis in children.
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PMID:[Use of tear enzyme assay to predict recurrent herpetic keratitis in children]. 1780 56

The four earliest developmentally controlled enzymes in the cellular slime mold, Dictyostelium discoideum, accumulate during axenic growth in rich media. We have shown that at low cell titers the specific activities of N-acetylglucosaminidase, alpha-mannosidase, leucine aminopeptidase, and alanine transaminase are each at very low or vegetative levels comparable to amoebae which have been grown on bacteria as the food source. During the exponential phase of growth all four enzymes accumulate dramatically reaching cellular specific activities at least as high as during development. The magnitude of this accumulation is influenced by alterations in the growth medium. We suggest that these results, combined with those of prior investigations, indicate that a restricted segment of early development is initiated during axenic growth. This means that growth and early development are not mutually exclusive events in this organism. The secretion of lysosomal enzymes is also affected by the composition of the growth media. In all media, including growth in bacterial suspensions, lysosomal enzymes are secreted in significant quantities. There is a correspondence in the effects of media composition on the secretion of these enzymes and on the regulation of developmentally controlled enzymes during axenic growth. The secretion of lysosomal enzymes that are not developmentally regulated is affected in these media, suggesting that the regulation and secretion of these enzymes are under separate control. It is clear that studies of the regulation of lysosomal enzymes in this organism must take into account the secretion of the enzymes as well as their cellular specific activities to properly reflect levels of gene expression.
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PMID:Regulation and secretion of early developmentally controlled enzymes during axenic growth in Dictyostelium discoideum. 2073 79