Transminase

Biochemical characteristics (plasma levels of alanine and aspartate transminases, alkaline phosphatase, triglycerides, cholesterol, urea, uric acid, allantoin, glucose, protein, albumin, sodium, potassium, calcium, magnesium, phosphorus urine levels of protein and glucose). 

A possible explanation for the superiority of the amino donor, L-aspartic add, has come from studies carried out on mutants of E. coli, in which only one of the three transaminases that are found in E. coli are present. It is believed that a branched chain transaminase, an aromatic amino add transaminase and an aspartate phenylalanine aspartase can be present in E. coli. The reaction of each of these mutants with different amino donors gave results which indicated that branched chain transminase and aromatic amino add transminase containing mutants were not able to proceed to high levels of conversion of phenylpyruvic add to L-phenylalanine. However, aspartate phenylalanine transaminase containing mutants were able to yield 98% conversion on 100 mmol l 1 phenylpyruvic acid. The explanation for this is probably that both branched chain transaminase and aromatic amino acid transminase are feedback inhibited by L-phenylalanine, whereas aspartate phenylalanine transaminase is not inhibited by L-phenylalanine. In addition, since oxaloacetate, which is produced when aspartic add is used as the amino donor, is readily converted to pyruvic add, no feedback inhibition involving oxaloacetate occurs. The reason for low conversion yield of some E. coli strains might be that these E. cdi strains are defident in the aspartate phenylalanine transaminase. 

Glutamate-pyruvate-transminase inhibition. Ethanol (50%) extract of the dried root, in cell culture at a concentration of... 

Dye, D.J., and Taberner, P.V. The effects of some newer anaesthetics on the in vitro activity of glutamate decarboxylase and GABA transminase in crude brain extracts and on the levels of amino acids in vivo. J. Neurochem. 24 997-1001, 1975. 

There are numerous transminases, each specific to a given substrate pair. Some may be primarily mitochondrial others, cytosolic. For example, glutamate-oxaloacetate transminase (GOT), also called aspartate aminotransferase (AST), is primarily a mitochondrial enzyme. AST is extensively used in the diagnosis of heart and liver disorders (see Chapter 5). The AST reaction is represented by Equation (20.7). 

GOT glutamic oxaloacetic transminase MIT metabolic inhibition test. 

SCOT serum glutamic oxalocetic transminase, SGPT serum glutamic pyruvic transaminase... 

H49. Hunt, A. H., and Lehmann, H., Serum albumin, pseudocholinesterase, and transminases in the assessment of liver function before and after venous shunt operations. Gut 1, 303-311 (1961). 

M16. Molander, D. W., Graver, L. F., and Packs, G. T., Liver enzymes, serum glutamic oxalacetic transminase, cholinesterase and alkaline phosphatase in primary and metastatic hepatic neoplasia. Acta Unio Int. Cancrum 16, 1478-1481 (1960). 

D5. Doberenz, A. R., Van Miller, J. P., Green, J. R., and Beaton, J. R., Vitamin B depletion in women using oral contraceptives as determined by erythrocyte glutamic-pyruvic transminase activities. Proc. Soc. Exp. Biol. Med. 137, 1100-1103 (1971). 

The enzymes glutamate-oxaloacetate transminase (GOI) is assayed by a coupled stem, having the following reactkais. 

A comparative quantitative assay of the rates of transamination of different amino acids in the different animal tissues using improved assay methods has not been reported. Unpublished studies from the author s laboratory reveal that the pattern of transaminase activity for different amino acids varies quantitatively as well as qualitatively. This difference also applies to the intracellular distribution of transminases. Glutamic-... 

Goerz and Orfanos (1978) treated 203 psoriatics with 75 mg/day etretinate for 3-4 weeks, followed by 50 mg/day for up to 6 months, followed by a 25-50 mg/day maintenance dose. Table VIII shows the number of patients experiencing side effects attributable to etretinate therapy in this study. Side effects such as hair loss, paronchia, and elevation of serum transminases caused discontinuation of treatment in 14% of the cases. 

Laboratory abnormalities associated with etretinate treatment are similar to those reported for isotretinoin with only transient elevations of transminases and serum triglycerides being those most commonly observed. Psoriatic patients, treated up to 4 weeks with 50-100 mg/day followed by a 25-50 mg/day maintenance dose, had increases in SCOT, SGPT, alkaline phosphatase, bilirubin, and prothrombin time (Mahrle et al., 1982) (Table VIII). 

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