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B6db references: 12568809

type Journal Article
authors Shibata, K.; Watanabe, T.; Yoshikawa, H.; Abe, K.; Takahashi, S.; Kera, Y.; Yamada, R.
title Purification and characterization of aspartate racemase from the bivalve mollusk Scapharca broughtonii
journal Comp Biochem Physiol B Biochem Mol Biol
sel selected
ui 12568809
year (2003)
volume 134
number 2
pages 307-314
abstract High concentrations of D-aspartate occur in blood shell Scapharca broughtonii (Mollusca) tissues. We purified aspartate racemase from the foot muscle of the bivalve to electrophoretic homogeneity. The molecular mass shown by sodium dodecyl sulfate polyacrylamide gel was 39 kDa, while that shown by gel filtration ranged from 51 to 63 kDa. Pyridoxal 5'-phosphate-dependency of the enzyme was demonstrated by its absorption spectrum as well as the effects of amino-oxyacetate and other reagents on the activity and spectrum. The enzyme is highly specific to aspartate and does not racemize L-alanine, L-serine and L-glutamate. It showed the highest activity at pH 8 both in the conversion of L- to D- and D- to L-aspartate, and the optimal temperature was 25 degrees C. V(max) and K(m) values for L-aspartate were 7.39 &mgr;molmin(-1)mg(-1) and 60.4 mM and those for D-aspartate were 22.6 &mgr;molmin(-1)mg(-1) and 159 mM, respectively.
last changed 2010/06/08 19:44

B6db references