Kohler H P, Kohler-Staub D, Focht D D
Department of Soil and Environmental Sciences, University of California, Riverside 92521.
Appl Environ Microbiol. 1988 Nov;54(11):2683-8. doi: 10.1128/aem.54.11.2683-2688.1988.
Pseudomonas sp. strain HBP1 was found to grow on 2-hydroxy- and 2,2'-dihydroxy-biphenyl as the sole carbon and energy sources. The first step in the degradation of these compounds was catalyzed by an NADH-dependent monooxygenase. The enzyme inserted a hydroxyl group adjacent to the already existing hydroxyl group to form 2,3-dihydroxybiphenyl when acting on 2-hydroxybiphenyl and to form 2,2',3-trihydroxybiphenyl when acting on 2,2'-dihydroxybiphenyl. To be substrates of the monooxygenase, compounds required a 2-hydroxyphenyl-R structure, with R being a hydrophobic group (e.g., methyl, ethyl, propyl, sec-butyl, phenyl, or 2-hydroxyphenyl). Several chlorinated hydroxybiphenyls served as pseudosubstrates by effecting consumption of NADH and oxygen without being hydroxylated. Further degradation of 2,3-dihydroxy- and 2,2',3-trihydroxybiphenyl involved meta cleavage, with subsequent formation of benzoate and salicylate, respectively.
假单胞菌属菌株HBP1被发现能以2-羟基联苯和2,2'-二羟基联苯作为唯一碳源和能源生长。这些化合物降解的第一步由一种依赖NADH的单加氧酶催化。该酶在作用于2-羟基联苯时，在已有的羟基相邻位置插入一个羟基形成2,3-二羟基联苯；在作用于2,2'-二羟基联苯时，形成2,2',3-三羟基联苯。作为单加氧酶的底物，化合物需要具有2-羟基苯基-R结构，其中R为疏水基团（如甲基、乙基、丙基、仲丁基、苯基或2-羟基苯基）。几种氯化羟基联苯作为假底物，通过消耗NADH和氧气但不被羟基化来发挥作用。2,3-二羟基联苯和2,2',3-三羟基联苯的进一步降解涉及间位裂解，随后分别形成苯甲酸酯和水杨酸酯。
