p1. Aldolase isoenzymes from guinea-pig cerebral cortex were partially purified and separated by ammonium sulphate fractionation and chromatography on DEAE-cellulose. 2. Each purified isoenzyme was shown to be virtually uncontaminated with other forms by starch-gel electrophoresis. The quantitative distribution of the isoenzymes was: I, 6·2%; II, 5·2%; III, 15·3%; IV, 25·7%; V, 33·3%. 3. The pH optima for the five separated isoenzymes were similar; all were in the range pH7·5–8·0. Values for piKsuba/sub/i (6·31–6·55) and piKsubb/sub/i (9·45–9·59) were calculated from the data and suggested the involvement of histidine and lysine residues. 4. The stabilities of the isoenzymes were shown to be I=II&III&IV&V at pH4·4 in order of decreasing stability and are discussed in terms of subunit structure. 5. The substrate activity ratios (fructose 1,6-diphosphate/fructose 1-phosphate) were measured and all were in the range 12–44./p
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机译：> 1。来自豚鼠大脑皮层的醛缩酶同工酶被部分纯化，并通过硫酸铵分级分离和DEAE-纤维素色谱法分离。 2.通过淀粉-凝胶电泳显示，每种纯化的同工酶实际上都未被其他形式污染。同工酶的定量分布为：I，6·2％; II，5·2％;三，15·3％; IV，25·7％; V，33·3％。 3.五个分离的同工酶的最适pH值相似;全部在pH7·5-8·0范围内。 p K a （6·31–6·55）和p K b （9·45）的值–9·59）是根据数据计算得出的，并暗示了组氨酸和赖氨酸残基的参与。 4.以降低稳定性的顺序，在pH4·4下，同工酶的稳定性显示为I ＝ II＞ III＞ IV＞ V，并就亚基结构进行了讨论。 5.测量底物活性比（果糖1,6-二磷酸/果糖1-磷酸），均在12-44之间。
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