STUDIES OF THE CATABOLIC PATHWAY OF DEGRADATION OF NITROBENZENE BY PSEUDOMONAS PSEUDOALCALIGENS JS45 - REMOVAL OF THE AMINO GROUP FROM 2-AMINOMUCONIC SEMIALDEHYDE
Zg. He et Jc. Spain, STUDIES OF THE CATABOLIC PATHWAY OF DEGRADATION OF NITROBENZENE BY PSEUDOMONAS PSEUDOALCALIGENS JS45 - REMOVAL OF THE AMINO GROUP FROM 2-AMINOMUCONIC SEMIALDEHYDE, Applied and environmental microbiology, 63(12), 1997, pp. 4839-4843
Pseudomonas pseudoalcaligenes JS45 utilizes nitrobenzene as the sole s
ource of nitrogen, carbon, and energy. Previous studies have shown tha
t degradation of nitrobenzene involves the reduction of nitrobenzene t
o nitrosobenzene and hydroxylaminobenzene, followed by rearrangement t
o 2-aminophenol, which then undergoes meta ring cleavage to 2-aminomuc
onic semialdehyde. In the present paper, we report the enzymatic react
ions responsible for the release of ammonia after ring cleavage. 2-Ami
nomuconic semialdehyde was oxidized to 2-aminomuconate in the presence
of NAD by enzymes in crude extracts. 2-Aminomuconate was subsequently
deaminated stoichiometrically to 4-oxalocrotonic acid. No cofactors a
re required for the deamination. Two enzymes, 2-aminomuconic semialdeh
yde dehydrogenase and a novel 2-aminomuconate deaminase, distinguished
by partial purification of the crude extracts, catalyzed the two reac
tions. 4-Oxalocrotonic acid was further degraded to pyruvate and aceta
ldehyde. The key enzyme, 2-aminomuconate deaminase, catalyzed the hydr
olytic deamination that released ammonia, which served as the nitrogen
source for growth of the organism.