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B6db references: 16616264

type Journal Article
authors Ono, K.; Yanagida, K.; Oikawa, T.; Ogawa, T.; Soda, K.
title Alanine racemase of alfalfa seedlings (Medicago sativa L.): First evidence for the presence of an amino acid racemase in plants
journal Phytochemistry
sel selected
ui 16616264
year (2006)
volume 67
pages 856-60
keywords Alanine Racemase/plants/eudicots
abstract We demonstrated several kinds of d-amino acids in plant seedlings, and moreover alanine racemase (E.C. in alfalfa (Medicago sativa L.) seedlings. This is the first evidence for the presence of amino acid racemase in plant. The enzyme was effectively induced by the addition of l- or d-alanine, and we highly purified the enzyme to show enzymological properties. The enzyme exclusively catalyzed racemization of l- and d-alanine. The K(m) and V(max) values of enzyme for l-alanine were 29.6x10(-3)M and 1.02mol/s/kg, and those for d-alanine are 12.0x10(-3)M and 0.44mol/s/kg, respectively. The K(eq) value was estimated to be about 1 and indicated that the enzyme catalyzes a typical racemization of both enantiomers of alanine. The enzyme was inactivated by hydroxylamine, phenylhydrazine and some other pyridoxal 5'-phosphate enzyme inhibitors. Accordingly, the enzyme required pyridoxal 5'-phosphate as a coenzyme, and enzymologically resembled bacterial alanine racemases studied so far.
last changed 2008/05/15 19:08

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