Alves A M, Euverink G J, Hektor H J, Hessels G I, van der Vlag J, Vrijbloed J W, Hondmann D, Visser J, Dijkhuizen L
Department of Microbiology, University of Groningen, Haren, The Netherlands.
J Bacteriol. 1994 Nov;176(22):6827-35. doi: 10.1128/jb.176.22.6827-6835.1994.
The actinomycete Amycolatopsis methanolica was found to employ the normal bacterial set of glycolytic and pentose phosphate pathway enzymes, except for the presence of a PPi-dependent phosphofructokinase (PPi-PFK) and a 3-phosphoglycerate mutase that is stimulated by 2,3-bisphosphoglycerate. Screening of a number of actinomycetes revealed PPi-PFK activity only in members of the family Pseudonocardiaceae. The A. methanolica PPi-PFK and 3-phosphoglycerate mutase enzymes were purified to homogeneity. PPi-PFK appeared to be insensitive to the typical effectors of ATP-dependent PFK enzymes. Nevertheless, strong N-terminal amino acid sequence homology was found with ATP-PFK enzymes from other bacteria. The A. methanolica pyruvate kinase was purified over 250-fold and characterized as an allosteric enzyme, sensitive to inhibition by P(i) and ATP but stimulated by AMP. By using mutants, evidence was obtained for the presence of transketolase isoenzymes functioning in the pentose phosphate pathway and ribulose monophosphate cycle during growth on glucose and methanol, respectively.
已发现甲醇拟无枝酸菌这种放线菌利用正常细菌的糖酵解和磷酸戊糖途径的一套酶，但存在一种焦磷酸依赖性磷酸果糖激酶（PPi-PFK）和一种受2,3-二磷酸甘油酸刺激的3-磷酸甘油酸变位酶。对多种放线菌的筛选表明，只有假诺卡氏菌科的成员中存在PPi-PFK活性。甲醇拟无枝酸菌的PPi-PFK和3-磷酸甘油酸变位酶被纯化至均一。PPi-PFK似乎对ATP依赖性PFK酶的典型效应物不敏感。然而，发现其与其他细菌的ATP-PFK酶有很强的N端氨基酸序列同源性。甲醇拟无枝酸菌的丙酮酸激酶被纯化了250多倍，并被鉴定为一种别构酶，对无机磷酸（P(i)）和ATP的抑制敏感，但受AMP刺激。通过使用突变体，获得了证据，表明在以葡萄糖和甲醇为生长底物时，分别有转酮醇酶同工酶在磷酸戊糖途径和核糖单磷酸循环中发挥作用。
