Formation of N-Acetylglutamate by Extracts of Higher Plants
AUTOR(ES)
Morris, Clayton J.
RESUMO
The enzymic synthesis of N-acetylglutamate was studied in extracts of higher plant tissues, especially in sugar beet leaves (Beta vulgaris L.). Sugar beet leaves had an enzyme that transferred the acetyl group either from acetyl-CoA or from N2-acetylornithine to glutamate. The enzyme was so unstable that special precautions were necessary for its detection and appreciable purification was impossible. The Km values were 2.5 and 0.025 mM for acetyl-CoA and N2-acetylornithine, respectively. The Km for glutamate was 23 mM with acetylornithine-glutamate transacetylase and 2.7 mM with acetyl-CoA-glutamate transacetylase. The pH optimum for acetyl-CoA-glutamate transacetylase was about 7.2 whereas that for acetylornithine-glutamate transacetylase was about 8.3. Acetylphosphate, N2-acetyl-2,4-diaminobutyrate, propionyl-CoA, and succinyl-CoA were not substrates.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=542473Documentos Relacionados
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