Troccaz Myriam, Benattia Faiza, Borchard Gerrit, Clark Anthony J
Firmenich SA, Corporate R&D Division, P. O. Box 239, CH-1211 Geneva 8.
Chem Biodivers. 2008 Nov;5(11):2372-85. doi: 10.1002/cbdv.200890202.
Enzymes implicated in cysteine and methionine metabolism such as cystathionine beta-lyase (CBL; EC 4.4.1.8), a pyridoxal-5'-phosphate (PLP)-dependent carbon-sulfur lyase, have been shown to play a central role in the generation of sulfur compounds. This work describes the unprecedented cloning and characterization of the metC-cystathionine beta-lyase from the axillary-isolated strain Staphylococcus haemolyticus AX3, in order to determine its activity and its involvement in amino acid biosynthesis, and in the generation of sulfur compounds in human sweat. The gene contains a cysteine/methionine metabolism enzyme pattern, and also a sequence capable to effect beta-elimination. The recombinant enzyme was shown to cleave cystathionine into homocysteine and to convert methionine into methanethiol at low levels. No odor was generated after incubation of the recombinant enzyme with sterile human axillary secretions; sweat components were found to have an inhibitory effect. These results suggest that the generation of sulfur compounds by Staphylococci and the beta-lyase activity in human sweat are mediated by enzymes other than the metC gene or by the concerted activities of more than one enzyme.
参与半胱氨酸和甲硫氨酸代谢的酶，如胱硫醚β-裂解酶（CBL；EC 4.4.1.8），一种依赖于磷酸吡哆醛（PLP）的碳-硫裂解酶，已被证明在硫化合物的生成中起核心作用。这项工作描述了从腋窝分离菌株溶血葡萄球菌AX3中前所未有的metC-胱硫醚β-裂解酶的克隆和表征，以确定其活性及其在氨基酸生物合成以及人类汗液中硫化合物生成中的作用。该基因包含半胱氨酸/甲硫氨酸代谢酶模式，还有一个能够进行β-消除的序列。重组酶被证明能将胱硫醚裂解为高半胱氨酸，并能将甲硫氨酸低水平转化为甲硫醇。将重组酶与无菌人类腋窝分泌物孵育后未产生气味；发现汗液成分具有抑制作用。这些结果表明，葡萄球菌产生硫化合物以及人类汗液中的β-裂解酶活性是由metC基因以外的酶或多种酶的协同活性介导的。
