Balch W E, Wolfe R S
J Bacteriol. 1979 Jan;137(1):264-73. doi: 10.1128/jb.137.1.264-273.1979.
A system for transport of coenzyme M, 2-mercaptoethanesulfonic acid (HS--CoM), in Methanobacterium ruminatium strain M1 required energy, showed saturation kinetics, and concentrated the coenzyme against a gradient. The process was sensitive to temperature and was maximally active at pH 7.1. Cells took up HS--CoM at a linear rate, with a Vmax of 312 pmol/min per mg (dry weight) and an apparent Km of 73 nM. An intracellular pool of up to 5 mM accumulated which was not exchangeable with the medium. Uptake required both hydrogen and carbon dioxide; it was inhibited by O2. Bromoethanesulfonic acid (BrCH2CH2SO3-), a potent inhibitor of methanogenesis in cell-free extracts, inhibited both uptake and methane production. Results of inhibitor studies with derivatives and analogs of the coenzyme showed that the specificity of the carrier is restricted to a limited range of thioether, thioester, and thiocarbonate derivatives. 2-(Methylthio)ethanesulfonic acid (CH3--S--CoM) showed an apparent Ki for HS--CoM uptake of 15 nM, being taken up itself with a Vmax of 320 pmol/min per mg (dry weight) and an apparent Km of 50 nM. An analysis of intracellular pools after HS--CoM uptake indicated that the predominant forms are a heterodisulfide of unknown composition and CH3--S--CoM.
反刍甲烷杆菌M1菌株中辅酶M（2-巯基乙烷磺酸，HS-CoM）的转运系统需要能量，呈现饱和动力学，且能逆浓度梯度浓缩该辅酶。此过程对温度敏感，在pH 7.1时活性最高。细胞以线性速率摄取HS-CoM，Vmax为每毫克（干重）312 pmol/分钟，表观Km为73 nM。可积累高达5 mM的细胞内池，且不可与培养基交换。摄取既需要氢气也需要二氧化碳；它受到氧气的抑制。溴乙烷磺酸（BrCH2CH2SO3-）是无细胞提取物中甲烷生成的有效抑制剂，可同时抑制摄取和甲烷生成。对该辅酶的衍生物和类似物进行抑制剂研究的结果表明，载体的特异性仅限于硫醚、硫酯和硫代碳酸盐衍生物的有限范围。2-（甲硫基）乙烷磺酸（CH3-S-CoM）对HS-CoM摄取的表观Ki为15 nM，其自身摄取的Vmax为每毫克（干重）320 pmol/分钟，表观Km为50 nM。HS-CoM摄取后对细胞内池的分析表明，主要形式是未知组成的杂二硫化合物和CH3-S-CoM。
