Characterization of a broad-range aldehyde dehydrogenase involved in alkane degradation in Geobacillus thermodenitrificans NG80-2.
An aldehyde dehydrogenase (ALDH) involved in alkane degradation in crude oil-degrading Geobacillus thermodenitrificans NG80-2 was characterized in vitro. The ALDH was expressed heterologously in Escherichia coli and purified as a His-tagged homotetrameric protein with a subunit of 57 kDa based on SDS-PAGE and Native-PAGE analysis. The purified ALDH-oxidized alkyl aldehydes ranging from formaldehyde (C₁) to eicosanoic aldehyde (C₂₀) with the highest activity on C₁. It also oxidized several aromatic aldehydes including benzaldehyde, phenylacetaldehyde, o-chloro-benzaldehyde and o-phthalaldehyde. The ALDH uses only NAD(+) as the cofactor, and has no reductive activity on acetate or hexadecanoic acid. Therefore, it is an irreversible NAD(+)-dependent aldehyde dehydrogenase. Kinetic parameters, temperature and pH optimum of the enzyme, and effects of metal ions, EDTA and Triton X-100 on the enzyme activity were investigated. Physiological roles of the ALDH for the survival of NG80-2 in oil reservoirs are discussed.
Li
Xiaomin
X
TEDA School of Biological Sciences and Biotechnology, Nankai University, 23 Hongda Street, TEDA, Tianjin 300457, PR China.
Li
Yanxia
Y
Wei
Dongmei
D
Li
Ping
P
Wang
Lei
L
Feng
Lu
L
D000444:Aldehyde Dehydrogenase / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D000473:Alkanes / Q000378:metabolism*; D002846:Chromatography, Affinity; D003067:Coenzymes / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D056506:Geobacillus / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008970:Molecular Weight; D009243:NAD / Q000378:metabolism; D010802:Phylogeny; D021122:Protein Subunits / Q000737:chemistry / Q000302:isolation & purification; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D013696:Temperature
D000473:Alkanes; D003067:Coenzymes; D021122:Protein Subunits; D011993:Recombinant Fusion Proteins; D009243:NAD; D000444:Aldehyde Dehydrogenase