Partial purification of γ-glutamyltransferase from human brain microvessels

Veselý, Jozef; Lisý, V.; Cernoch, M

doi:10.1007/bf00964975

Cited by 4 publications

(4 citation statements)

References 33 publications

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“…We have shown that for γ-glutamyl p-nitroanilide and glycyl glycine, in the platelets of normal subjects, the K m values were calculated as 2.1 mM and 15.9 mM respectively (Yardimci et al, 1995). It was reported in the literature that in human brain capillaries, the partially purified GGT had optimum pH between 8.2 and 9 (Vesely et al, 1985). The K m value of human liver GGT, when γ-glutamyl p-nitroanilide was used as the substrate, was reported as 1.4 mM, and for kidney it was 1.2 mM.…”

Section: Yardimci 2000)mentioning

confidence: 83%

“…Purification of neutrophil GGT The method of Vesely et al (1985) was used with some modifications. Triton X-100 solubilized neutrophil fractions from nine subjects were first pooled and then precipitated with ammonium sulphate (45-90% saturation).…”

Section: Methodsmentioning

confidence: 99%

“…L-serine inhibits GGT in the presence of borate by interacting with the γ-glutamyl binding site of the enzyme (Tate and Meister, 1978;Vesely et al, 1985). Purified rat deciduoma had an optimum pH of 8.2 and a K m value of 1 mM for γ-glutamyl p-nitroanilide and 7.6 mM for glycylglycine.…”

Section: Yardimci 2000)mentioning

confidence: 99%

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Activity Determination, Kinetic Analyses and Isoenzyme Identification of Gamma Glutamyltransferase in Human Neutrophils

Şener¹,

Yardımcı²

2005

BMB Reports

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Gamma-glutamyltransferase (GGT, EC 2.3.2.2) which hydrolyzes glutathione (GSH), is required for the maintenance of normal intracellular GSH concentration. GGT is a membrane enzyme present in leukocytes and platelets. Its activity has also been observed in human neutrophils. In this study, GGT was purified from Triton X-100 solubilized neutrophils and its kinetic parameters were determined. For kinetic analyses of transpeptidation reaction, γ-glutamyl p-nitroanilide was used as the substrate and glycylglycine as the acceptor. Apparent K m values were determined as 1.8 mM for γ-glutamyl pnitroanilide and 16.9 mM for glycylglycine. The optimum pH of GGT activity was 8.2 and the optimum temperature was 37ºC. It had thermal stability with 58% relative activity at 56ºC for 30 min incubation. L-serine, in the presence of borate, was detected as the competetive inhibitor. Bromcresol green inhibited neutrophil GGT activity as a noncompetetive inhibitor. The neutrophils seem to contain only the isoenzyme that is present in platelets. We characterized the kinetic properties and compared the type of the isoenzyme of neutrophil GGT with platelet GGT via polyacrylamide gel electrophoresis (PAGE) under a standart set of conditions.

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Section: Yardimci 2000)mentioning

confidence: 83%

Section: Methodsmentioning

confidence: 99%

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Activity Determination, Kinetic Analyses and Isoenzyme Identification of Gamma Glutamyltransferase in Human Neutrophils

Şener¹,

Yardımcı²

2005

BMB Reports

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“…It was reported in the literature that L-serine (which is another essential amino acid)inhibits GGT in the presence of borate by interacting with the gamma-glutamyl binding site of the enzyme (Tate and Meister,1978;Vesely et al ,1985).GGT activity is increased in a number of primary and metastatic tumers (Dominici et al,2003). It has been shown that hepatocellular carcinoma can be expressed hepatoma specific GGT and secreted GGT in to circulating blood (Yao et al,1998).…”

Section: B Discussionmentioning

confidence: 99%

Serum gamma-glutamyltransferase activity: Inhibitory study in patient of hepatitis

Talabani¹

2013

IOSR-JAC

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Elevation of gamma-glutamyltransferase (GGT) activity has been implicated in many pathologies, and clinical inhibitors of GGT are under development for use in the treatment of liver ,cancer, bone, and other diseases. In this study we try to find other new inhibitor of GGT, we used new polar amino acid (threonine) as inhibitor ,kinetic studies provide insight into the mechanism of inhibition. New uncompetitive inhibitors of physiological GGT reaction we found, development of new inhibitors is essential for exploiting GGT as a therapeutic target. L-threonine, in the presence study was detected as uncompetitive inhibitor, Km values were determined; we characterized the kinetic properties of GGT under a standard set of condition. Serum GGT was analyzed in healthy cases (normal 25:mean±SD) age 30±12 years,(16.71±0.87), the mean values of GGT levels were statistically significantly higher in liver syndrome(70.79±1.24),and this values decreased in the presence of inhibitor to (60.82±0.87).

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Extrahepatic Drug‐Metabolizing Enzymes and Their Significance

Jhajra

Varkhede

Ahire

et al. 2012

Encyclopedia of Drug Metabolism and Interactions

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Drug‐metabolizing enzymes (DMEs) are primarily expressed in the liver but their role in the extrahepatic tissues such as gastrointestinal tract (GIT), pulmonary, excretory, nervous, cardiovascular system, and skin cannot be neglected. Generally, the expression of DMEs in extrahepatic tissues is quantitatively lower than that in the liver, but there are a few enzymes such as CYP1A1, CYP1B1, CYP2F1, and CYP2U1 that are more abundant in extrahepatic organs. As many extrahepatic organs are portals for administered drugs, DMEs expressed in these organs can be responsible for significant metabolism, leading to first‐pass effects and lower bioavailability. Extrahepatic DMEs are also involved in bioactivation of prodrugs and formation of reactive metabolites that may interact with cellular components, resulting in organ‐specific toxicity. Activity and expression of extrahepatic DMEs is often altered by coadministered drugs, leading to drug–drug interactions. Expression of DMEs in living beings affected by a host of environmental and genetic factors such as genetic polymorphism, age, gender, pathophysiological conditions, inborn errors in metabolism, food habits, and environmental pollutants, contributing to varied drug effects and idiosyncratic toxicities.

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Partial purification of γ-glutamyltransferase from human brain microvessels

Cited by 4 publications

References 33 publications

Activity Determination, Kinetic Analyses and Isoenzyme Identification of Gamma Glutamyltransferase in Human Neutrophils

Activity Determination, Kinetic Analyses and Isoenzyme Identification of Gamma Glutamyltransferase in Human Neutrophils

Serum gamma-glutamyltransferase activity: Inhibitory study in patient of hepatitis

Extrahepatic Drug‐Metabolizing Enzymes and Their Significance

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