Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10841995 | Plant Science | 2005 | 6 Pages |
Abstract
Biochemical properties of a polyamine oxidase (PAO; EC 1.5.3.3) purified from the aquatic nitrogen-fixing fern Azolla imbricata (Roxb.) Nak. were studied. The native molecular mass of the enzyme estimated by Sephadex G 200 gel filtration was 66.2Â kDa. SDS-PAGE gave a single protein band corresponding to a molecular mass of 65.5Â kDa. The light yellow enzyme had absorption maxima at 278, 372 and 454Â nm with 1Â mol FAD per mole enzyme molecule as its cofactor. The PAO was active on both the triamine Spd and the tetraamine Spm as substrates. However, it was inactive on the diamines Put and Cad. It had a pH optimum of 6.5 for both Spd and Spm. The Kms for Spd and Spm were 6.71Â ÃÂ 10â2 and 1.13Â ÃÂ 10â1Â mM, respectively. Pre-incubation with 10Â mM of K+ (KCl), Ca2+ (CaCl2) or Mg2+ (MgCl2) had no effect on PAO activity. However, 10Â mM Cu2+ (CuCl2), Mn2+ (MnCl2) and Fe2+ (FeSO4) inhibited enzyme activity by 37%, 43% and 58%, respectively. The metal chelator EDTA (10Â mM), the carbonyl reagent hydroxylamine (0.5Â mM) and the sulfhydryl reagent p-chloro-mercuribenzoate (0.5Â mM) had no effect on PAO activity.
Keywords
SDSpolyamine oxidasespCMBPAGESPMFMNflavin adenine dinucleotideSPDPAOp-ChloromercuribenzoateEDTAEthylenediaminetetraacetic acidSpermineSpermidineUltravioletpolyacrylamide gel electrophoresisAmine oxidasesFADPropertiesDAOsodium dodecyl sulfateCADflavin mononucleotideputrescinePUTMichaelis constantPurificationPolyaminepolyamine oxidaseAPAOCadaverine
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Plant Science
Authors
Sheng-Gen He, Daryl Joyce, Ming-Zu Wang,