Metabolic control analysis of L-cysteine producing strain TS1138 of Pseudomonas sp.
A kinetic model describing the biosynthesis of L-cysteine by Pseudomonas sp. TS1138 has been developed. The two enzymes catalyzing this pathway, L-cysteine synthetase (CS) and L-cysteine desulfhydrase (CD), follow Michaelis-Menten kinetics with noncompetitive inhibition of CS by L-cysteine. From measurements of intermediates and end products that were made during L-cysteine enzymatic synthesis, metabolic control analysis of the pathway was carried out using the kinetic model. The elasticity coefficients and the flux control coefficients were calculated, and the analysis revealed a shift in the flux control from CS to CD during the reaction. The findings further implicate potential targets and strategies for increasing L-cysteine production; for example, the strain TS1138 could be manipulated by site-directed mutagenesis to reduce CD activity.
College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, P. R. China. huailihua2007@yahoo.com.cn
Lihua
L
Huai
Ning
N
Chen
Wenbo
W
Yang
Gang
G
Bai
D000581:Amidohydrolases / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism; D003542:Cystathionine gamma-Lyase / Q000378:metabolism; D003545:Cysteine / Q000096:biosynthesis* / Q000737:chemistry; D025461:Feedback, Physiological; D007700:Kinetics; D053858:Metabolic Networks and Pathways; D015394:Molecular Structure; D011549:Pseudomonas / Q000201:enzymology* / Q000378:metabolism*
D001426:Bacterial Proteins; D000581:Amidohydrolases; D003542:Cystathionine gamma-Lyase; D003545:Cysteine