Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have characterized the binding of gamma-glutamyltransferase to three insolubilized lectins. Optimal binding was achieved in 2 hours at 25 degrees C for concanavalin A and at 4 derees C for ricinus communis agglutinin 120 and wheat germ agglutinin,and was also a function of the ratio of lectin protein to gamma-glutamyltransferase protein. The interaction of gamma-glutamyltransferase with these three lectins is specific, and release of bound enzyme by carbohydrates follows the same general order of specificity previously observed for the competition between mono or polysaccharides for the lectin carbohydrate binding sites. The binding of trypsin-solubilized liver gamma-glutamyltransferase to the three insolubilized lectins was virtually identical to that of detergent solubilized enzyme. We propose, therefore, that the release by proteolytic enzymes, of gamma-glutamyltransferase from plasma membrane matrix does not significantly alter its carbohydrate structure. We obtained great differences in binding to the three lectins between the liver, kidney, pancreatic and duodenal isoenzymes of gamma-glutamyltransferase. From this data we conclude that carbohydrate content and topography are important distinguishing features of gamma-glutamyltransferase isoenzymes.
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PMID:Interaction of gamma-glutamyltransferase from human tissues with insolubilized lectins. 4 83

The releases of proteins, maltase, lactase, sucrase, trehalase, alkaline phosphatase, gamma-glutamyltransferase and leucylnaphthylamide-hydrolyzing activity from human intestinal brush bborder membrane vesicles by various enzymes (especially pancreatic proteases) have been studied. The brush border membrane enzymes are not solubilized by digestion with trypsin and chymotrypsin but are largely released after treatment with papain or elastase. Most of the enzymes are fully active after the proteolytic treatment. All proteins released by papain and elastase have been identified by electrophoresis to already known intestinal hydrolases. Electron microscopy of brush border membrane vesicles demonstrates "knob-like" structures (particles) attached to the external side of the membrane. During papain treatment, enzyme removal runs parallel with the disappearance of the particles. During elastase treatment it is not possible to correlate the release of the enzymic activities with the removal of the particles. The results indicate that most of the intestinal hydrolases are surface components attached to the external side of the membrane. They are in accord with the concept that the brush border membrane enzymes are organized within the membrane in a mosaic-like pattern.
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PMID:Enzymic solubilization of the human intestinal brush border membrane enzymes. 127 90

Urinary excretion of alpha-glucosidase (AGL), gamma-glutamyltransferase (GGT) and ribonuclease (RNase), and serum amylase and immunoreactive trypsin (IRT) were determined in 38 control subjects, 48 patients with pancreatic cancer, 77 with chronic pancreatitis and 47 with extrapancreatic diseases in order to ascertain the presence of a renal tubular damage and to investigate its etiology. A significantly increased frequency of pathological results for all urinary enzymes was documented in the various groups of patients as compared to controls. Significant correlations were detected among AGL, GGT and RNase. Considering the subjects as a whole, GGT and RNase excretions correlated with serum IRT and amylase; the two urinary enzymes were found to be higher when jaundice was present. In chronic pancreatic disease enzymuria was related to increased serum pancreatic enzymes; in extrapancreatic diseases it was associated to hyperbilirubinemia. The vast majority of patients with pancreatic cancer and elevated urinary enzymes presented hepatic metastases and/or jaundice. We can conclude that an anatomical and functional tubular impairment is detectable in some patients with chronic pancreatic and extrapancreatic diseases. Tubular damage seems to least in part to be related to pancreatic inflammation and necrosis in chronic pancreatic disease, while jaundice may be found to play an important role in diseases of the hepatobiliary tract. In pancreatic cancer, liver dysfunction (presence of liver metastases and/or extrahepatic cholestasis) also appears to be involved in altering tubular cells.
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PMID:Renal tubular dysfunction in pancreatic cancer and chronic pancreatitis. 256 74

The vitamin E deficiency was studied for its effect on the activity of enzymes participating in metabolism of xenobiotics. Experiments with 54 rats have demonstrated that the maintenance of animals on the vitamin-E-deficient diet within 13-14 weeks decreases the activity of microsomal monooxygenases (demethylase and hydroxylase), NADH- and NADPH-reductases, aryl- and aliesterases in the liver and lungs, which is a result of disturbance of hydrophobic and polar interactions in microsomal membranes. Vitamin E deficiency makes the extent of solubilization of these enzymes higher under the influence of deoxycholate and trypsin and intensifies inactivation of these enzymes under the effect of urea. In the lungs and in the liver of the vitamin E deficient rats the content of reduced glutathione decreases as well as the activity of glutathione reductase, glutathione-S-transferase, aldehyde dehydrogenase, while the activity of gamma-glutamyltransferase increases; glutathione disulphide is accumulated.
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PMID:[The effect of vitamin E deficiency on enzyme activity and the status of the membrane fraction of rat liver microsomes]. 258 40

Duodenal aspirates were obtained before, during, and after stimulation with secretin-cholecystokinin in 26 patients whose pancreatic function was classified as normal, moderately reduced, or severely reduced. The activities of gamma-glutamyltransferase (GGT), alkaline phosphatase (ALP), and 5'-nucleotidase (5NT) in the aggregated duodenal aspirate collected 10-40 min after stimulation showed marked overlap between the functional groups and lacked diagnostic value. For all three enzymes, the peak response occurred later in the severely impaired group than in those with normal pancreatic function. The three enzymes showed significant positive correlations with each other, and were negatively correlated with the output of trypsin and chymotrypsin and, in contrast with these proteolytic enzymes which were reduced in pancreatic disease, GGT, ALP, and 5NT all tended to increase with pancreatic disease. Contrary to a previous report, GGT did not serve as a useful index of pancreatic cancer in this study.
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PMID:Activities of gamma-glutamyl transferase, 5'-nucleotidase and alkaline phosphatase in human duodenal aspirate. 287 69

In order to investigate the role of circulating free trypsinogen and renal tubular dysfunction in affecting trypsin plasma-urine transfer, serum immunoreactive trypsin (IRT), its urinary output, IRT molecular size distribution, filtrable immunoreactive trypsin, gamma-glutamyltransferase and alpha-glucosidase outputs were studied in 6 control subjects, 9 patients with pancreatic cancer and 15 with chronic pancreatitis. The majority of immunoreactivity was always eluted at a molecular weight of about 24,000 and might therefore be considered as free trypsinogen. Variable amounts of IRT at higher molecular weights, possibly represented by trypsin-inhibitor complexes, were also detected. Increasing IRT levels were generally accounted for by free trypsinogen, regardless of the nature of the disease. Unlike serum free trypsinogen levels, renal tubular damage, evaluated by means of the excretion of two high-molecular weight urinary enzymes, seems to play a prominent role in explaining trypsin plasma-urine transfer.
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PMID:Molecular size distribution of immunoreactive trypsin and renal tubular dysfunction: role in trypsin plasma-urine transfer. 288 33

In order to investigate the role of renal factors in affecting trypsinogen 1 metabolism and excretion in chronic pancreatic disease, serum immunoreactive trypsin (IRT), urinary IRT, gamma-glutamyltransferase (GGT), alpha-glucosidase (AGL) and RNase outputs and the molecular size distribution of serum and urine IRT were studied in 8 control subjects, 18 cases with pancreatic cancer, and 23 cases with chronic pancreatitis. Serum chromatography demonstrated that most immunoreactivity eluted as trypsinogen 1. Smaller amounts of immunoreactivity at higher molecular weights were also observed. Urine chromatography displayed both trypsinogen 1 and heavier molecular forms. An inverse linear correlation was noticed between creatinine clearance and serum trypsinogen 1 levels. Multiple regression analysis (urinary IRT output dependent and GGT, AGL, and RNase predictor variables) showed a significant linear correlation. RNase was found to be the most important parameter in explaining urinary IRT output. Mild variations in the glomerular function seem to be able to influence serum trypsinogen 1 levels. Urinary IRT excretion is principally explained by a disturbance in the tubular reabsorption of low molecular weight proteins, such as RNase.
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PMID:Renal factors in serum trypsinogen 1 metabolism and excretion in chronic pancreatic disease. 336 41

The properties of gamma-glutamyltransferase in homogenates of human kidney were investigated by measuring its susceptibility to inactivation by heating at 56 degree C. In freshly prepared homogenates, or after short storage at -20 degree C, the enzyme was observed to be relatively heat-stable. However, it could be transformed into a heat-labile form by treatment with thiol compounds or the proteolytic enzymes trypsin and papain. This process was not necessarily accompanied by solubilisation of the enzyme from the particulate fraction of the homogenate. The addition of 1 mmol/1 glutathione during the heating step completely protected the enzyme against heat inactivation in either the relatively heat-stable form or the heat-labile form produced as a result of prior treatment with enzymes or thiol reagent. The observation that glutathione concentrations lower than the apparent Km for glutathione as a substrate fully protect the enzyme against heat inactivation suggests that the enzyme contains a second binding site for glutathione. This second site would be of higher affinity for glutathione than the substrate-binding site but would not itself participate in the enzyme reaction.
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PMID:Heat inactivation of gamma-glutamyltransferase in homogenates of human kidney. 612 31

Several forms of gamma-glutamyltransferase have been prepared from human liver, bile and serum by size-dependent means, and have been subjected to digestions with trypsin, neuraminidase and phospholipases, extraction with deoxycholate and organic solvents, and freezing and thawing, to attempt to elucidate their nature and interrelationships. In general, these treatments alter the size and charge of the original fractions, producing in some cases resemblances between originally distinct fractions. All the forms appear to contain a catalytically active component of less than 20,000 molecular weight, which may be the small subunit of a common enzyme molecule. The observations are consistent with the view that multiple forms of gamma-glutamyltransferase in human serum and bile arise by various modifications of a single type of enzyme.
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PMID:Multiple forms of human gamma-glutamyltransferase: modification and possible structures of different molecular weight fractions. 612 1

The three brush-border enzymes--alanine aminopeptidase (EC 3.4.11.2), alkaline phosphatase (EC 3.1.3.1), and gamma-glutamyltransferase (EC 2.3.2.2)--are present in the urine of healthy persons in two variants, a particulate form and a soluble one. They can be separated by electrophoresis in agarose gel and by ultracentrifugation. The particulate forms exhibit similar electrophoretic mobility, but the soluble forms of these brush-border enzymes differ in their electrophoretic mobilities. The enzyme components of the particulate activity can be mobilized by Triton X-100 and trypsin. The electrophoretic mobility of the soluble forms of alanine aminopeptidase and gamma-glutamyltransferase is slowed by neuraminidase treatment. Both forms of gamma-glutamyltransferase are influenced in their electrophoretic mobility by treatment with n-butanol/diisopropyl ether, showing their lipid dependence. These findings enhance our knowledge of the biochemical nature of brush-border enzymes in urine.
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PMID:Electrophoretic variants of alanine aminopeptidase, alkaline phosphatase, and gamma-glutamyltransferase in urine. 614 5


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