Oxidation of acetylpolyamines by maize polyamine oxidase

Article abstract of DOI:10.1016/0031-9422(96)00316-0

The oxidation of acetylpolyamines by celt wall polyamine oxidase from maize shoots was investigated. The purified enzyme catalysed the oxidation of N¹-acetylspermine, N¹-acetylspermidine, and N⁸-acetylspermidine at the same optimal pH (6.5), but with lower relative velocities and higher K(m) than those found for spermine and spermidine oxidation. The enzyme cleaved N¹-acetylspermine and N⁸-acetylspermidine, at the same positions as in spermine and spermidine oxidation, with the production of H₂O₂, 1,3- diaminopropane and the corresponding aminoaldehydes. Polyamine oxidase was quickly inactivated by catalysis, and the aminoaldehyde derived from N¹- acetylspermine behaved as a competitive inhibitor of the enzyme (K(m) = 20 μM). These findings suggest that cell wait polyamine oxidase from maize shoots does not effect the interconversion pathway of acetylpolyamines found in vertebrates.