Stribling D, Perham R N
Biochem J. 1973 Apr;131(4):833-41. doi: 10.1042/bj1310833.
Two fructose diphosphate aldolases (EC 4.1.2.13) were detected in extracts of Escherichia coli (Crookes' strain) grown on pyruvate or lactate. The two enzymes can be resolved by chromatography on DEAE-cellulose at pH7.5, or by gel filtration on Sephadex G-200, and both have been obtained in a pure state. One is a typical bacterial aldolase (class II) in that it is strongly inhibited by metal-chelating agents and is reactivated by bivalent metal ions, e.g. Ca(2+), Zn(2+). It is a dimer with a molecular weight of approx. 70000, and the K(m) value for fructose diphosphate is about 0.85mm. The other aldolase is not dependent on metal ions for its activity, but is inhibited by reduction with NaBH(4) in the presence of substrate. The K(m) value for fructose diphosphate is about 20mum (although the Lineweaver-Burk plot is not linear) and the enzyme is probably a tetramer with molecular weight approx. 140000. It has been crystallized. On the basis of these properties it is tentatively assigned to class I. The appearance of a class I aldolase in bacteria was unexpected, and its synthesis in E. coli is apparently favoured by conditions of gluconeogenesis. Only aldolase of class II was found in E. coli that had been grown on glucose. The significance of these results for the evolution of fructose diphosphate aldolases is briefly discussed.
在以丙酮酸或乳酸为碳源生长的大肠杆菌（克鲁克斯菌株）提取物中，检测到两种果糖二磷酸醛缩酶（EC 4.1.2.13）。这两种酶可以通过在pH7.5条件下于DEAE - 纤维素上进行色谱分离，或通过在Sephadex G - 200上进行凝胶过滤来分离，并且二者均已获得纯品。一种是典型的细菌醛缩酶（II类），它受到金属螯合剂的强烈抑制，并能被二价金属离子（如Ca(2 +)、Zn(2 +)）重新激活。它是一种二聚体，分子量约为70000，果糖二磷酸的K(m)值约为0.85mmol/L。另一种醛缩酶的活性不依赖于金属离子，但在底物存在的情况下会被NaBH(4)还原所抑制。果糖二磷酸的K(m)值约为20μmol/L（尽管Lineweaver - Burk图不是线性的） , 并且该酶可能是一种分子量约为140000的四聚体。它已经结晶。基于这些特性，它被初步归为I类。细菌中出现I类醛缩酶是出乎意料的，并且它在大肠杆菌中的合成显然受到糖异生条件的促进。在以葡萄糖为碳源生长的大肠杆菌中只发现了II类醛缩酶。本文简要讨论了这些结果对果糖二磷酸醛缩酶进化的意义。
