title: Cloning of two 5-aminolevulinic acid synthase isozymes HemA and HemO from Rhodopseudomonas palustris with favorable characteristics for 5-aminolevulinic acid production.
abstract: 5-Aminolevulinic acid (ALA) synthase (ALAS) HemA from non-sulfur photosynthetic bacteria has been used for the ALA bioproduction, whereas the isoenzyme HemT/HemO is less studied and not used for ALA production. Two ALAS-encoding genes, hemA and hemO from Rhodopseudomonas palustris were cloned, purified and characterized. The ALASs had very high specific activity, 3.6 and 2.7 U/mg, respectively, and strong affinity for one of its substrates, succinyl-CoA, K m with values of 11 and 4.4 μM, respectively. HemO retained up to 60 % maximum activity within a broad range of concentrations of hemin, while HemA kept only 20 % at 10 μM hemin. Escherichia coli overexpressing HemA or HemO produced 5.7 and 6.3 g ALA/l, respectively, in a 5 l bioreactor.
authors: College of Biotechnology, Tianjin University of Science and Biotechnology, Tianjin 300457, People's Republic of China. liluzhang@126.com
authors: Lilu
authors: L
authors: Zhang
authors: Jiuzhou
authors: J
authors: Chen
authors: Ning
authors: N
authors: Chen
authors: Jibin
authors: J
authors: Sun
authors: Ping
authors: P
authors: Zheng
authors: Yanhe
authors: Y
authors: Ma
mesh_terms: D000624:5-Aminolevulinate Synthetase / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000622:Aminolevulinic Acid / Q000032:analysis / Q000378:metabolism*; D003001:Cloning, Molecular / Q000379:methods*; D004591:Electrophoresis, Polyacrylamide Gel; D006427:Hemin / Q000494:pharmacology; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012241:Rhodopseudomonas / Q000201:enzymology* / Q000235:genetics
chemical_list: D007527:Isoenzymes; D011994:Recombinant Proteins; D006427:Hemin; D000622:Aminolevulinic Acid; D000624:5-Aminolevulinate Synthetase