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B6db references: tyrebbaz

type Journal Article
authors Esaki, N.; Watanabe, M.; Kurihara, T.; Soda, K.
title Fungal thermostable α-dialkylamino acid aminotransferase: occurrence, purification and characterization
journal Arch Microbiol
Activity 4.1.1.64
ui Tyrebbaz
year (1994)
volume 61
number 2
pages 110-5.
 
abstract a-Dialkylamino acid aminotransferase was found in various fungi; this is the first evidence for the occurrence of the enzyme in eukaryotes. The enzyme was purified from Fusarium solani and shown to be composed of four subunits with an identical molecular weight of 42,000. a-Aminoisobutyrate and cycloleucine served as amino donors, and pyruvate, a-ketobutyrate, a-ketovalerate, a-ketoisovalerate, and glyoxylate as amino acceptors. The K m values for a-aminoisobutyrate and a-ketobutyrate were 28 and 0.3 mM, respectively. a-Ketobutyrate inhibited the enzyme noncompetitively with a-aminoisobutyrate, and showed K i value of 8 mM. The significant inhibitory effect of l-cycloserine was observed, but d-cycloserine did not inhibit the enzyme. The pH and temperature optima for transamination of a-aminoisobutyrate with pyruvate were about 8.0 and 60?C, respectively. Despite the production of this enzyme by the mesophile, the enzyme was thermostable; it retained its full activity upon heating at 60?C for 30 min.
last changed 2004/05/26 13:46

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