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type Journal Article
authors Kuan YC, Kao CH, Chen CH, Chen CC, Hu HY, Hsu WH
title Biochemical characterization of a novel lysine racemase from Proteus mirabilis BCRC10725
journal Process Biochem
sel selected
ui NOTinPub_Med
year (2011)
volume 46
number 10
pages 1914-20
keywords doi 10.1016/j.procbio.2011.06.019
abstract A lysine racemase gene (lyr) that consisted of an open reading frame of 1224-bp and encoded a protein with a calculated molecular mass of 45 kDa was cloned from the Proteus mirabilis BCRC10725 and expressed in Escherichia coli BL21(DE3). The purified His6-tagged Lyr was most active towards lysine, exhibiting a specific activity of 2828 97 U/mg. This enzyme also racemized arginine with a specific activity of 568 28 U/mg but not other amino acids. The optimal conditions for Lyr activity to l-lysine were pH 8.09.0 and 50 C. The racemization activity of Lyr was completely inhibited by 5 mM hydroxylamine and was partially restored by the addition of pyridoxal 5′-phosphate. The S394 residue of Lyr was subjected to site-directed mutagenesis. The arginine racemization activities of the S394Y, S394N, S394C and S394T variant proteins were increased by 1.51.8 fold compared to the wild-type Lyr, indicating that the S394 residue played a crucial role in determining the preference of Lyr to lysine and arginine.
last changed 2017/12/06 10:35

B6db references