Some properties of the NADP-malic enzyme from mango fruit, Mangifera indica

1. 1. Malic enzyme l-malate-NADP-oxidoreductase (oxaloacetate-decarboxylating) (EC 1.1.1.40) was located in the cytosolic fraction of ripening mango fruit. 2. 2. The purified enzyme has an isoelectric point of 6.86 and an activation energy of 11.9kcal/mol. 3. 3. The amino acid composition of the enzyme was determined and revealed a low cysteine and tryptophan content. 4. 4. The enzyme has an ultraviolet absorption maximum at 266 nm with maxima for fluorescence excitation and emission at 285 and 328 nm. 5. 5. The enzyme shows positive cooperativity between the malate binding sites and the effect of allosteric regulators and structural analogues on the activity were investigated.