乙酸菌糖磷酸化作用的研究

SUGAR PHOSPHORYLATION ACTIVITIES IN ACETOGENIC BACTERIA

对７ 种乙酸菌（ Ａｃｅｔｉｔｏｍａｃｕｌｕｍ ｒｕ ｍｉｎｉｓ， Ａｃｅｔｏｂａｃｔｅｒｉｕｍ ｗｏｏｄｉｉ， Ｅｕｂａｃｔｅｒｉｕ ｍ ｌｉｍｏｓｕ ｍ 和分离株Ａ２ 、Ａ４ 、Ａ１０ 、Ｈ３ＨＨ） 的葡萄糖和２脱氧葡萄糖磷酸化作用进行了研究。尽管所有机体都存在磷酸化反应，但它们在依赖ＰＥＰ 和ＡＴＰ 的比例上有实质性区别。分离菌株Ａ１０ 具有最高的依赖ＰＥＰ 的葡萄糖磷酸化活力（１１６２ｎｍｏｌ·Ｌ－１·ｍｇ － １·ｍｉｎ － １） ，Ａ１０ 、Ｈ３ＨＨ和Ｅ．ｌｉｍｏｓｕｍ 都具有葡萄糖磷酸转移酶系统（ｐｈｏｓｐｈｏｔｒａｎｓｆｅｒａｓｅ ｓｙｓｔｅｍ ，ＰＴＳ） 。相反，Ａ．ｒｕｍｉｎｉｓ、Ａ．ｗｏｏｄｉｉ、Ａ２ 和Ａ４ 则不具有ＰＴＳ活力。这七株菌的葡萄糖依赖ＡＴＰ 的磷酸化活力都高于依赖ＰＥＰ的磷酸化活力，但其程度有所不同。Ａ１０ 和Ｈ３ＨＨ 的葡萄糖ＰＴＳ可通过胞外葡萄糖诱导，并且其比活在对数期随培养时间延长而增加。此外，还检测到Ａ１０

Seven acetogenic bacteria (Acetitomaculum ruminis, Acetobacterium woodii, Eubacterium limosum as well as isolates A2, A4, A10 and H3HH)were tested for PEP and ATP dependent phosphorylation of glucose and 2 deoxyglucose. Although all organisms had detectable phosphorylation activity, substantial variation existed in the rates of both PEP and ATP dependent phosphorylation. Isolate Alo had the highest rate of PEP depehdent phosphorylation of 11 62 nmol·L -1 ·mg -1 ·min -1 .Isolate A10, H3HH as well as E.limosum most likely have a glucose phosphotransferase system(PTS). In contrast, A ruminis, A. woodii and isolate A2, A4 had PEP dependent glucose phosphorylation rates very similar to control rates, suggesting the lack of PTS activity. The rates of ATP dependent glucose phosphorylation were higher than PEP dependent phoshorylation in all organisms surveyed. However, substantial variation existed in the rates of ATP dependent glucose phosphorylation. The glucose PTS of isolates A10 and H3HH were induced by the presence of extracellular glucose. Moreover, the specific activity of the glucose PTS of both isolates increased as cultures progressed from the early log to late log phase of gowth. ATP and PEP dependent maltose and sucrose phosphorylation was detected in isolates A10 and H3HH. Although activity was detected in both isolates(A10 and H3HH), the rate of activity varied considerably, depending on the sugar and organism tesed.