Sakai H, Ohta T
Department of Agricultural Chemistry, Faculty of Agriculture, University of Tokyo, Japan.
Eur J Biochem. 1993 Feb 1;211(3):851-9. doi: 10.1111/j.1432-1033.1993.tb17618.x.
Pyruvate kinase from Bacillus stearothermophilus is an allosteric enzyme activated by AMP or ribose 5-phosphate but not by fructose 1,6-bisphosphate. The gene for the enzyme was cloned in Escherichia coli and its entire nucleotide sequence was determined. The deduced amino acid sequence consisted of 587 residues and the molecular mass was calculated to be 62 317 Da. The sequence was highly similar to other pyruvate kinases, indicating that they have the same evolutional origin. Similarly to the E. coli enzymes, the enzyme does not contain an N-terminal domain, in contrast to the eukaryotic pyruvate kinases. However, the Bacillus stearothermophilus enzyme had an extra C-terminal sequence consisting of about 110 amino acid residues. A phosphoenolpyruvate-binding motif, which is observed in pyruvate phosphate dikinase, phosphoenolpyruvate: sugar phosphotransferase system enzyme I and phosphoenolpyruvate synthase, was present in the extra C-terminal sequence. There was an open reading frame upstream of the pyruvate kinase gene. The homology of the sequence showed that the gene encodes phosphofructokinase. Both phosphofructokinase and pyruvate kinase were expressed in E. coli cells, and the evidence suggesting that both genes constitute an operon is presented.
嗜热脂肪芽孢杆菌的丙酮酸激酶是一种别构酶，可被AMP或5-磷酸核糖激活，但不能被1,6-二磷酸果糖激活。该酶的基因在大肠杆菌中克隆，并测定了其完整的核苷酸序列。推导的氨基酸序列由587个残基组成，计算分子量为62317 Da。该序列与其他丙酮酸激酶高度相似，表明它们有相同的进化起源。与大肠杆菌的酶类似，该酶不含N端结构域，这与真核生物的丙酮酸激酶不同。然而，嗜热脂肪芽孢杆菌的酶有一个由约110个氨基酸残基组成的额外C端序列。在丙酮酸磷酸双激酶、磷酸烯醇丙酮酸：糖磷酸转移酶系统酶I和磷酸烯醇丙酮酸合酶中观察到的磷酸烯醇丙酮酸结合基序存在于额外的C端序列中。丙酮酸激酶基因上游有一个开放阅读框。序列同源性表明该基因编码磷酸果糖激酶。磷酸果糖激酶和丙酮酸激酶都在大肠杆菌细胞中表达，并提供了表明这两个基因构成一个操纵子的证据。
