L-alanine:2-oxoglutarate aminotransferase

L-Alanine 2-oxoglutarate aminotransferase Alanine arninotransferase (transaminase) ALT... 

The aminotransferases constitute a group of enzymes that catalyze the interconversion of amino acids to 2-oxo-acids by transfer of amino groups. Aspartate aminotransferase (EC 2.6.1.1 L-aspartate 2-oxoglutarate aminotransferase AST) and alanine aminotransferase (EC 2.6.1.2 L-alanine 2-oxoglutarate aminotransferase ALT) are examples of aminotransferases that are of clinical interest. 

L-alanine 2-oxoglutarate Alanine aminotransferase (ALT) (also known... 

The soluble and particulate alanine 2-oxoglutarate aminotransferases of tomato fruits (which may be identical proteins) (Rech and Crouzet, 1974 Gazeu-Reyjal and Crouzet, 1976) are estimated to have molecular weights of 100,000 (gel filtration). Some plant transaminases are evidently much smaller. Ornithine 2-oxoacid aminotransferase has a molecular weight estimated at 48,000 (Lu and Mazelis, 1975), and a molecular weight of 56,200 has been determined for L-alanine 5-ketooctanal aminotransferase from Conium maculatum (Roberts, 1977). Although very few estimates are available, and not many alternative methods have been used, it seems clear that the molecular weights of plant transaminases vary considerably from one enzyme to another. They may also differ from comparable animal enzymes (Lu and Mazelis, 1975). 

Amination of aldehydes by an amino acid aldehyde aminotransferase from Mercurialis perennis was inhibited strongly by pyruvate, oxaloacetate, and oxoglutarate, and this inhibition was suspected to be competitive (Hartmann et al., 1972). Formation of coniceine by an alanine 5-keto-octanal aminotransferase was inhibited competitively by pyruvate and uncompetitively by glyoxylate (Roberts, 1978). With the L-ornithine 2-oxoacid aminotransferase from Cucurbita pepo, severe inhibition by valine, leucine, and isoleucine could be observed, but there was no inhibition by lysine or proline (Lu and Mazelis, 1975). Cucurbita maxima ornithine aminotransferase, however, was reported to be inhibited by proline (Splittstoesser and Fowden, 1973), as well as by canavanine and diaminobutyrate. 

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