Y-glutamyl transferases and

Serum aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, y-glutamyl transferase, and bilirubin may be elevated in patients with hepatobiliary disease. 

Thus, these similar examples illustrate that GSH conjugation may not always lead to a reduction in toxicity. Furthermore, they illustrate that several factors are responsible for the kidney being the target organ active uptake processes, the presence of p-lyase and y-glutamyl transferase, and possibly the importance of mitochondria in the brush border membranes, which are the ultimate target. 

Similarly, transient elevations of AST, ALT, y-glutamyl transferase, and LDH were observed in dogs following the administration of 0.6g/kg doses of o-Raff-Hb. The changes were related to liver catabolism of this acellular Hb. 

The vast majority of people who become ill with HAV com-pletely recover. HAV infection usually produces a self-limited illness that lasts less than 2 months, although 10% to 15% of patients exhibit a cholestatic illness with predominant elevations of alkaline phosphatase, y -glutamyl transferase, and total bilhubin that continues or is relapsing for up to 6 months. Pruritus is often a major complaint... 

Enzymes, measured in clinical laboratories, for which kits are available include y-glutamyl transferase (GGT), alanine transferase [9000-86-6] (ALT), aldolase, a-amylase [9000-90-2] aspartate aminotransferase [9000-97-9], creatine kinase and its isoenzymes, galactose-l-phosphate uridyl transferase, Hpase, malate dehydrogenase [9001 -64-3], 5 -nucleotidase, phosphohexose isomerase, and pymvate kinase [9001-59-6]. One example is the measurement of aspartate aminotransferase, where the reaction is followed by monitoring the loss of NADH ... 

Activities of glutamate-pyruvate transaminase (SGPT, GPT) (EC 2.6.1.2), L-y -glutamyl-transferase (y-GT) (EC 2.3.2.2) and level of triglycerides (TG) in serum, as well as levels of glutathione (GSH) and malondialdehyde (MDA) in the liver were determined. 

Cholestasis (increased total bilirubin, direct bilirubin, alkaline phosphatase, and y-glutamyl transferase)... 

Fig. 4.2 Hydrolytic activity of cauxin on 3-MBCG and proposed metabolic pathways for the conversion of 3-MBG to felinine in the cat kidney. The 3-MBCG (20 mM) was incubated with or without cauxin (1.5 mg/ml) at 38°C for 6 h, and the reaction mixtures were analyzed by thin layer chromatography with ninhydrin staining. y-GTP, y-glutamyl transferase RDP, renal dipeptidase a, 3-mercapto-3-methylbutyl formate b, 3-mercapto-3-methyl-l-butanol c, 3-methyl-3-methylthio-1-butanol and d, 3-methyl-3-(2-methyldisulfanyl)-l-butanol...

Aside from the Maillard reaction, other covalent modifications of amino acids and proteins are possible within the caries lesion, which merit future investigation. For example, certain oral microorganisms excrete y-glutamyl transferases. These enzymes catalyse the formation of cross-links between glutamic acid and lysine residues of proteins. In addition, N-acyl amino acids are present in plaque, which adsorb to mineral surfaces. 

Cook, N. D. and Peters, T. J. (1985) Purification of y-glutamyl transferase by phenyl boronate affinity chromatography. Biochim. Biophys. Acta 828,205—212. 

Tadalafil pharmacokinetics in patients with ED showed linear relation with respect to dose and duration of treatment, and a one-compartment model adequately described the data. The absorption rate was rapid (1.86 h ), and the t)q)ical population estimates of the apparent oral clearance (CL/F) and apparent volume of distribution were 1.6 L/h and 63.8 L, respectively. Disposition parameters showed a moderate degree of interindividual variability (39-45%). The value of CL/F decreased slightly with increasing serum y-glutamyl transferase (GGT) concentration, the only statistically significant covariate detected. Systemic exposure to tadalafil was not influenced by age, weight, smoking status, alcohol consumption, liver enz nne status, ED severity, cardiovascular condition, or diabetes mellitus. 

The term enzymatic markers of cholestasis (or cholestasis-indicating enzymes) comprises alkaline phosphatase, leucine aminopeptidase (or leucine arylamidase) as well as 5 -nucleotidase and y-glutamyl transferase, (see chapter 13)... 

The incidence of raised liver enzymes during therapy with oral isotretinoin 1 mg/kg/day for acne has been retrospectively reviewed in 876 patients (57). Liver enzymes (aspartate transaminase, alanine transaminase, and y-glutamyl transferase) were transiently raised in a minority of patients (number not stated). 

In the assay described here cells are permeablized using a detergent-based lysis method. Care must be taken to inhibit the membrane-bound enzyme, y glutamyl-transferase (y-GT), which metabolizes glutathione released from the cell (12). This is achieved by the use of an acidified lysis buffer (8). The lysate is then assayed for total protein and glutathione content. 

Enzymes in this category include alanine and aspartate aminotransferases, glutamate dehydrogenase (GLD), ATP, 5 -nucleotidase (NTP), y-glutamyl transferase (GGT), glutathione S-transferase (GST), and serum cholinesterase (CHE). The aminotransferases and ALP are widely used. They have long been mistakenly called, as a group, liver function tests. They are not, of course, but the habit persists. GGT is widely available in the United States and on automated analyzers. The others have not been adopted as widely. 

There are five enzymes that are commonly used in diagnosis of liver disease Aspartate aminotransferase (AST EC 2.6.1.1), alanine aminotransferase (ALT EC 2.6.1.2), alkaline phosphatase (ALP 3.1.3.1), and y-glutamyl transferase (GGT EC 2.3.2.2), are commonly used to detect liver injury, and lactate dehydrogenase (LD EC 1.1.1.27) is occasionaEy used. ALT and GGT are present in several tissues, but plasma activities primarily reflect liver injury. AST is found in liver, muscle (cardiac and skeletal), and to a liipited extent iti fed cells. LD has wide tissue distribution, and is thus relatively nonspecific. ALP is found in a number of tissues, but in normal individuals primarEy reflects bone and liver sources. Thus based on tissue distribution, ALT and GGT would seem to be the most specific markers for liver injury. 

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