Claiborne A, Malinowski D P, Fridovich I
J Biol Chem. 1979 Nov 25;254(22):11664-8.
The second heme-containing hydroperoxidase isozyme (HP-II) has been isolated from aerobic cultures of Escherichia coli B. The protein exists as a stable tetramer of subunits of equal size, with a combined molecular weight of 312,000. The heme spectrum of HP-II is unusual, in that it exhibits two absorbance maxima at 407 and 591 nm; the alkaline pyridine hemochromogen spectrum shows maxima at 425, 559, and 609 nm. HP-II differs in several respects from the HP-I isozyme previously reported (Claiborne, A., and Fridovich, I. (1979) J. Biol. Chem. 254, 4245-4252). Thus HP-II is virtually devoid of peroxidatic activity toward o-dianisidine but has a 6-fold higher catalatic activity than HP-I. Antisera to HP-II do not cross-react with HP-I, and analyses of chymotryptic and cyanogen bromide digests suggest differences in primary structure between these two isozymes.
已从大肠杆菌B的需氧培养物中分离出第二种含血红素的氢过氧化物酶同工酶（HP-II）。该蛋白质以大小相等的亚基组成的稳定四聚体形式存在，总分子量为312,000。HP-II的血红素光谱不同寻常，它在407和591nm处有两个吸光度最大值；碱性吡啶血色原光谱在425、559和609nm处有最大值。HP-II在几个方面与先前报道的HP-I同工酶不同（克莱伯恩，A.，和弗里多维奇，I.（1979年）《生物化学杂志》254，4245 - 4252）。因此，HP-II对邻联茴香胺几乎没有过氧化物酶活性，但催化活性比HP-I高6倍。针对HP-II的抗血清与HP-I不发生交叉反应，胰凝乳蛋白酶和溴化氰消化产物的分析表明这两种同工酶的一级结构存在差异。
