Purification and Some Properties of a 2-Hydroxy-6-oxo-6-phenylhexa-2, 4-dienoic Acid Hydrolyzing Enzyme from Pseudomonas cruciviae S93 Bl involved in the Degradation of Biphenyl

抄録

A 2-hydroxy-6-oxo-6-phenylhexa-2, 4-dienoic acid (HOPDA) hydrolyzing enzyme was purified to a homogeneous state from P. cruciviae S93 Bl grown on biphenyl as the carbon source. The enzyme hydrolyzed HOPDA between the C₅-C₆ bond to produce benzoic acid and 2-oxopent-4-enoic acid. The HOPDA hydrolyzing enzyme had a molecular weight of about 160, 000, and was dissociated in SDS, with prior treatment with mercaptoethanol, into a single subunit with an approximate molecular weight of 29, 000. The optimum pH of this hydrolase was 4.7, and it was relatively stable in an alkaline solution. It attacked the meta ring-fission products of biphenyl-2, 3-diol, 3-isopropylcatechol, 3-methylcatechol and catechol. It was proposed that this enzyme is called 2, 6-dioxo-6-phenylhexa-3-enoic acid (DPEA) by hydrolase and is classified under the number EC 3.7.1.