Matheis G, Belitz H D
Z Lebensm Unters Forsch. 1979 Sep;169(3):165-9. doi: 10.1007/BF01333317.
Gel chromatography on Sepharose and on Sephadex was used to separate the soluble phenol oxidase in various potato juices into multiple molecular forms ranging from 36,000 to 800,000 daltons. Adjustment of potato juice from physiological pH (ca. 6) to pH 4.5 or to pH 7.8 resulted in the predominance of low-mol.-wt. (less than 150,000 daltons) or high-mol.-wt. (greater than 150,000 daltons) enzyme forms, respectively. This suggests association phenomena of subunits. In potato juice of physiological pH and in potato juice adjusted to pH 4.5, all enzyme forms exhibited both monophenol and o-diphenol oxidase activities (assayed at pH 6.0). In potato juice adjusted to pH 7.8 considerable loss of monophenol oxidase activity (assayed at pH 6.0) occurred. This suggests that o-diphenol oxidase is more alkali-stable than monophenol oxidase. The significance of these findings for enzyme purifications and for the in vivo action of the enzyme is discussed.
采用琼脂糖凝胶色谱法和葡聚糖凝胶色谱法，将各种马铃薯汁中的可溶性酚氧化酶分离成分子量范围从36,000到800,000道尔顿的多种分子形式。将马铃薯汁从生理pH值（约6）调节至pH 4.5或pH 7.8，分别导致低分子量（小于150,000道尔顿）或高分子量（大于150,000道尔顿）酶形式占主导。这表明存在亚基的缔合现象。在生理pH值的马铃薯汁以及调节至pH 4.5的马铃薯汁中，所有酶形式均表现出单酚氧化酶和邻二酚氧化酶活性（在pH 6.0下测定）。在调节至pH 7.8的马铃薯汁中，单酚氧化酶活性（在pH 6.0下测定）出现相当大的损失。这表明邻二酚氧化酶比单酚氧化酶更耐碱。讨论了这些发现对酶纯化以及酶在体内作用的意义。
