Zq. He et al., PURIFICATION, CHARACTERIZATION, AND SEQUENCE-ANALYSIS OF 2-AMINOMUCONIC 6-SEMIALDEHYDE DEHYDROGENASE FROM PSEUDOMONAS PSEUDOALCALIGENES JS45, Journal of bacteriology, 180(17), 1998, pp. 4591-4595
2-Aminonumconic B-semialdehyde is an unstable intermediate in the biod
egradation of nitrobenzene and 2-aminophenol by Pseudomonas pseudoalca
ligenes JS45, Previous work has shown that enzymes in cell extracts co
nvert 2-aminophenol to 2-aminomuconate in the presence of NAD(+), In t
he present work, 2-aminomuconic semialdehyde dehydrogenase was purifie
d and characterized, The purified enzyme migrates as a single band on
sodium dodecyl sulfate-polyacrylamide gel electrophoresis with a molec
ular mass of 57 kDa, The molecular mass of the native enzyme was estim
ated to be 160 kDa by gel filtration chromatography, The optimal pH fo
r the enzyme activity was 7.3. The enzyme is able to oxidize several a
ldehyde analogs, including 2-hydroxymuconic semialdehyde, hexaldehyde,
and benzaldehyde. The gene encoding 2-aminomuconic semialdehyde dehyd
rogenase was identified by matching the deduced N-terminal amino acid
sequence of the gene with the first 21 amino acids of the purified pro
tein. Multiple sequence alignment of various semialdehyde dehydrogenas
e protein sequences indicates that 2-aminomuconic 6-semialdehyde dehyd
rogenase has a high degree of identity with 2-hydroxymuconic 6-semiald
ehyde dehydrogenases.