Guenthner T M, Karnezis T A
Drug Metab Dispos. 1986 Mar-Apr;14(2):208-13.
Benzo(a)pyrene 4,5-oxide (BPO) hydrolase activity and trans-stilbene oxide hydrolase activity were measured in human lung samples obtained from 12 different patients. These activities, attributable to different epoxide hydrolases, were both found in significant amounts in the cytosolic as well as the microsomal cell fractions. The catalytic properties of human lung BPO hydrolases were further investigated, and similarities between the cytosolic and microsomal forms of this enzyme were noted. Similar Km values were found for both forms (22 microM for the microsomal enzyme, 37 microM for the cytosolic enzyme). Both forms responded in similar fashion to a number of enzyme inhibitors in vitro, and the IC50 values for each inhibitor were the same for both forms. Both forms of the enzyme were inhibited uncompetitively by trichloropropene oxide, and the Kii value for the cytosolic hydrolase (11 microM) was similar to that obtained for the microsomal hydrolase (15 microM). These two forms of BPO hydrolase in the human lung are very similar, possibly identical, enzymes.
在取自12位不同患者的人肺样本中测定了苯并(a)芘4,5-氧化物（BPO）水解酶活性和反式芪氧化物水解酶活性。这些活性归因于不同的环氧化物水解酶，在胞质溶胶以及微粒体细胞组分中均大量存在。对人肺BPO水解酶的催化特性进行了进一步研究，并注意到该酶的胞质溶胶形式和微粒体形式之间的相似性。两种形式的Km值相似（微粒体酶为22μM，胞质溶胶酶为37μM）。两种形式在体外对多种酶抑制剂的反应方式相似，每种抑制剂的IC50值对于两种形式均相同。两种形式的酶均被三氯丙烯氧化物非竞争性抑制，胞质溶胶水解酶的Kii值（11μM）与微粒体水解酶的Kii值（15μM）相似。人肺中的这两种形式的BPO水解酶是非常相似、可能相同的酶。
