Kozak M, Hayward B, Borek D, Bonthron D T, Jaskólski M
Department of Macromolecular Physics, Faculty of Physics, A. Mickiewicz University, Umultowska 85, 61-614 Poznañ, Poland.
Acta Crystallogr D Biol Crystallogr. 2001 Apr;57(Pt 4):586-8. doi: 10.1107/s0907444901001007.
Ketohexokinase (KHK; E.C. 2.7.1.3) catalyses the (reversible) phosphorylation of fructose to fructose-1-phosphate. KHK is the first enzyme in a specialized catabolic pathway metabolizing dietary fructose to the glycolytic intermediate glyceraldehyde-3-phosphate. Mutations inactivating KHK underlie the metabolic disorder essential fructosuria. The primary structure of KHK shows no significant homology to other mammalian hexokinases. It is most similar to prokaryotic ribokinases, but catalyses a distinct phosphorylation reaction. Recombinant human KHK has been crystallized in the orthorhombic form (space group P2(1)2(1)2 or P2(1)2(1)2(1)). Single crystals of this polymorph suitable for X-ray diffraction have been obtained by vapour diffusion using 2-propanol and MPD as precipitants (pH 7.5). The crystals have unit-cell parameters a = 93.4, b = 121.5, c = 108.4 A. Diffraction data were collected to 4.3 A resolution. The asymmetric unit contains four protein molecules.
酮己糖激酶（KHK；酶学委员会编号2.7.1.3）催化果糖（可逆）磷酸化生成1-磷酸果糖。KHK是将膳食果糖代谢为糖酵解中间产物3-磷酸甘油醛的特定分解代谢途径中的首个酶。使KHK失活的突变是遗传性果糖不耐受症这一代谢紊乱疾病的病因。KHK的一级结构与其他哺乳动物己糖激酶无显著同源性。它与原核生物核糖激酶最为相似，但催化不同的磷酸化反应。重组人KHK已结晶为正交晶型（空间群P2(1)2(1)2或P2(1)2(1)2(1)）。通过以2-丙醇和MPD作为沉淀剂（pH 7.5）的气相扩散法获得了适合X射线衍射的该多晶型的单晶。晶体的晶胞参数为a = 93.4、b = 121.5、c = 108.4 Å。收集了分辨率达4.3 Å的衍射数据。不对称单元包含四个蛋白质分子。
