Purification, N-terminal sequence determination and enzymatic characterization of antiquitin from the liver of grass carp.
Aldehyde dehydrogenase (ALDH) is a superfamily of enzymes catalyzing the conversion of various aldehydes to the corresponding acids using the coenzymes NAD+ or NADP+. While mammalian ALDHs have been studied extensively, the non-mammalian ALDHs, notably those of teleostean origin, remain relatively unexplored. In our previous study on grass carp (Ctenopharyngodon idellus) liver ALDH, a significant amount of the ALDH activity did not adsorb on the alpha-cyanocinnamate Sepharose column which binds ALDH2. The objective of the present study was to purify the ALDH which accounts for this unadsorbed activity. Further chromatography on Affi-gel Blue agarose, followed by size exclusion on Superdex 200 successfully isolated this aldehyde-oxidizing activity. The protein was a homo-tetramer with a subunit molecular mass of 58 kDa. N-terminal sequencing of the first 21 amino acid residues, followed by blastp analysis on the NCBI database revealed the protein as antiquitin. The optimal pH for the oxidation of acetaldehyde was 9.5. At this pH, the Vmax and the Km values for acetaldehyde were 1.95 U/mg and 2.00 mM, respectively.
Department of Biochemistry, The Chinese University of Hong Kong, Shatin, NT, Hong Kong, PR China.
Wing-Man
WM
Chan
Wai-Kwan
WK
Tang
Christopher H K
CH
Cheng
Wing-Ping
WP
Fong
D000444:Aldehyde Dehydrogenase / Q000737:chemistry / Q000302:isolation & purification*; D000595:Amino Acid Sequence; D000818:Animals; D002347:Carps / Q000378:metabolism*; D002846:Chromatography, Affinity; D004591:Electrophoresis, Polyacrylamide Gel; D008099:Liver / Q000201:enzymology*; D008969:Molecular Sequence Data; D011506:Proteins / Q000737:chemistry / Q000302:isolation & purification*; D020539:Sequence Analysis, Protein; D017386:Sequence Homology, Amino Acid
D011506:Proteins; C089507:ALDH7A1 protein, human; D000444:Aldehyde Dehydrogenase