On the possibility of involvement of glutamate:glyoxylate and serine:glyoxylate aminotransferases from rye (Secale cereale L.) seedlings in the metabolism of tetrapyrrole compounds.
The activity of highly purified L-serine:glyoxylate aminotransferase (SGAT, EC 2.6.1.45) from rye seedlings was inhibited competitively by 5-aminolevulinate (ALA, Ki = 5 mM) SGAT was activated by hematin. Protoporphyrin IX and hematin inhibited irreversibly the activity of highly purified glutamate:glyoxylate aminotransferase (GGAT, EC 2.6.1.2) from rye seedlings. SGAT was found to catalyse transamination between ALA and hydroxypyruvate, whereas GGAT that between ALA and 2-oxoglutarate or pyruvate. It is suggested that SGAT is involved in the process of degradation of the excess ALA which has not been incorporated into porphyrin compounds.
Paszkowski
A
A
Department of Biochemistry, Faculty of Agriculture, Warsaw Agricultural University, Poland.
D006038:Glyoxylates / Q000378:metabolism; D007700:Kinetics; D011758:Pyrroles / Q000378:metabolism*; D012434:Secale / Q000201:enzymology* / Q000378:metabolism; D012694:Serine / Q000378:metabolism; D013379:Substrate Specificity; D045725:Tetrapyrroles; D000637:Transaminases / Q000378:metabolism*
D006038:Glyoxylates; D011758:Pyrroles; D045725:Tetrapyrroles; D012694:Serine; D000637:Transaminases; C020649:glutamate-glyoxylate aminotransferase; C022636:serine-glyoxylate aminotransferase