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B6db references: 29691793

type Journal Article
authors Md Harun-Ur-Rashid, Iwasaki H, Parveen S, Oogai S, Fukuta M, Hossain M, Anai T, Oku H
title Cytosolic Cysteine Synthase Switch Cysteine and Mimosine Production in Leucaena leucocephala
journal Appl Microbiol Biotechnol.
sel selected
ui 29691793
year (2018)
volume 186
number 3
pages 613-632
keywords 2,5-dimethyl-3-pyridinol; Cysteine; Mimosine; O-acetylserine(thiol)lyase; α-aminoacrylate; β-cyanoalanine synthase; β-substituted alanine synthase
abstract In higher plants, multiple copies of the cysteine synthase gene are present for cysteine biosynthesis. Some of these genes also have the potential to produce various kinds of β-substitute alanine. In the present study, we cloned a 1275-bp cDNA for cytosolic O-acetylserine(thiol)lyase (cysteine synthase) (Cy-OASTL) from Leucaena leucocephala. The purified protein product showed a dual function of cysteine and mimosine synthesis. Kinetics studies showed pH optima of 7.5 and 8.0, while temperature optima of 40 and 35 C, respectively, for cysteine and mimosine synthesis. The kinetic parameters such as apparent Km, kcat were determined for both cysteine and mimosine synthesis with substrates O-acetylserine (OAS) and Na2S or 3-hydroxy-4-pyridone (3H4P). From the in vitro results with the common substrate OAS, the apparent kcat for Cys production is over sixfold higher than mimosine synthesis and the apparent Km is 3.7 times lower, suggesting Cys synthesis is the favored pathway.
last changed 2018/10/23 12:09

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