Wilson J M, Kelley W N
J Biol Chem. 1984 Jan 10;259(1):27-30.
HPRTMunich is a mutant form of human hypoxanthine-guanine phosphoribosyltransferase that was isolated from a patient who presented with gout and a partial deficiency of enzyme activity. Profound abnormalities in the catalytic function of HPRTMunich are responsible for the deficiency of enzyme activity in vivo. Tryptic peptides of HPRTMunich were mapped by reverse phase high pressure liquid chromatography in an attempt to define the precise abnormality in its primary structure. Sequence analysis of aberrant peptides localized the structural alteration in HPRTMunich to residue 103. Several additional findings suggest that the mutation in this variant is most likely a serine to arginine substitution at residue 103. This amino acid substitution lies within the putative hypoxanthine-binding site of human hypoxanthine-guanine phosphoribosyltransferase possibly explaining its selective effect on intrinsic enzyme activity and binding of hypoxanthine.
HPRT慕尼黑是人类次黄嘌呤-鸟嘌呤磷酸核糖转移酶的一种突变形式，它是从一名患有痛风且酶活性部分缺乏的患者中分离出来的。HPRT慕尼黑催化功能的严重异常是体内酶活性缺乏的原因。通过反相高压液相色谱法对HPRT慕尼黑的胰蛋白酶肽段进行图谱分析，试图确定其一级结构中的精确异常。对异常肽段的序列分析将HPRT慕尼黑的结构改变定位到第103位残基。其他一些发现表明，该变体中的突变很可能是第103位残基处丝氨酸被精氨酸取代。这种氨基酸取代位于人类次黄嘌呤-鸟嘌呤磷酸核糖转移酶假定的次黄嘌呤结合位点内，这可能解释了它对内在酶活性和次黄嘌呤结合的选择性影响。
