Koga S, Yoshioka I, Sakuraba H, Takahashi M, Sakasegawa S, Shimizu S, Ohshima T
Department of Diagnostics Research & Development, Asahi Chemical Industry Co., Ltd., Mifuku, Ohito, Tagata, Shizuoka 410-2321, Japan.
J Biochem. 2000 Dec;128(6):1079-85. doi: 10.1093/oxfordjournals.jbchem.a022836.
The ADP-dependent (AMP-forming) glucokinases from the hyperthermophilic archaea Pyrococcus furiosus and Thermococcus litoralis catalyze the phosphorylation of glucose using ADP as the essential phosphoryl group donor. Both enzymes were purified to homogeneity and characterized with regard to each other. The enzymes had similar enzymological properties as to substrate specificity, coenzyme specificity, optimum pH, and thermostability. However, a difference was observed in the subunit composition; while the T. litoralis enzyme is a monomer with a molecular mass of 52 kDa, the P. furiosus enzyme has a molecular mass of about 100 kDa and consists of two subunits with identical molecular masses of 47 kDa. The genes encoding these enzymes were cloned and sequenced. The gene for the P. furiosus enzyme contains an open reading frame for 455 amino acids with a molecular weight of 51,265, and that for the T. litoralis enzyme contains an open reading frame for 467 amino acids with a molecular weight of 53,621. About 59% similarity in amino acid sequence was observed between these two enzymes, whereas they did not show similarity with any ATP-dependent kinases that have been reported so far. In addition, two phosphate binding domains, and adenosine and glucose binding motifs commonly conserved in the eukaryotic hexokinase family were not observed.
嗜热古菌激烈火球菌（Pyrococcus furiosus）和嗜热栖热菌（Thermococcus litoralis）中依赖二磷酸腺苷（生成一磷酸腺苷）的葡萄糖激酶，利用二磷酸腺苷作为必需的磷酰基供体催化葡萄糖磷酸化。两种酶均被纯化至同质，并相互进行了特性鉴定。这两种酶在底物特异性、辅酶特异性、最适pH值和热稳定性等酶学性质方面相似。然而，在亚基组成上观察到差异；嗜热栖热菌的酶是分子量为52 kDa的单体，而激烈火球菌的酶分子量约为100 kDa，由两个分子量均为47 kDa的亚基组成。编码这些酶的基因被克隆并测序。激烈火球菌酶的基因包含一个455个氨基酸的开放阅读框，分子量为51,265，嗜热栖热菌酶的基因包含一个467个氨基酸的开放阅读框，分子量为53,621。这两种酶之间氨基酸序列的相似性约为59%，然而它们与迄今报道的任何依赖三磷酸腺苷的激酶均无相似性。此外，未观察到真核己糖激酶家族中常见的两个磷酸结合结构域以及腺苷和葡萄糖结合基序。
