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B6db references: 8537297

type Journal Article
authors Jhee, K. H.; Yoshimura, T.; Esaki, N.; Yonaha, K.; Soda, K.
title Thermostable ornithine aminotransferase from Bacillus sp. YM-2: purification and characterization
journal J Biochem (Tokyo)
sel selected
ui 8537297
year (1995)
volume 118
number 1
pages 101-8
keywords Sequence
abstract Thermostable L-ornithine: alpha-ketoglutarate delta-aminotransferase (L- ornithine: 2-oxo-acid 5-aminotransferase) [EC] was purified to homogeneity from Bacillus sp. YM-2. The enzyme has a molecular weight of about 82,000 and consists of two subunits with identical molecular weights. The enzyme catalyzes transamination from L-ornithine to alpha- ketoglutarate, producing L-glutamate and L-glutamate gamma- semialdehyde, which is spontaneously dehydrated to L-delta 1-pyrroline- 5-carboxylate, and the enzyme is most active at 70 degrees C. In addition to L-ornithine, the enzyme unexpectedly acts on D-ornithine, the reaction rate being 6% of that for L-ornithine. The enzyme contains 1 mol each of pyridoxal 5'-phosphate and another vitamin B6 compound per mol. The enzyme released the bound pyridoxal 5'-phosphate, as judged from the absorption at 425 nm on incubation with 2.0 M guanidine hydrochloride. The resultant inactive enzyme still gave a 340-nm peak and contained 1 mol of the vitamin B6 compound. The partial amino acid sequence shows high homology with those of mammalian and yeast ornithine delta-aminotransferases.
last changed 2018/01/23 11:29

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