Properties of the polyamine oxidase from the cell wall of maize seedlings

Polyamine oxidase was purified 4.8-fold from the cell wall extract of maize seedlings using only two chromatographic steps. The enzyme (Mr ca 53 000) which had a specific activity of 700 nkat/mg at 37° showed a similar pH optimum (6.5) with both spermidine and spermine as substrates. For spermine and spermidine the Kms were 18 and 22 μM respectively. The light yellow enzyme had absorption maxima at 278, 380 and 456 nm. The addition in anaerobic conditions of equimolar amounts of substrates induced a decrease of A at 380 and 456 nm, while reoxygenation of the enzyme restored the native spectrum. The enzyme contained 2.5% sugar, mainly as arabinose.