Intracellular localisation of some peptidases and alpha-mannosidase in cotyledons of resting kidney bean, Phaseolus vulgaris

Cotyledons of resting kidney beans (Phaseolus vulgaris, L., cv. “Processor”) contain high activities of two alkaline peptidases, an aminopeptidase (EC 3.4.11) acting on Leu-Tyr and Leu-Gly-Gly and a dipeptidase (EC 3.4.13) hydrolysing Ala-Gly together with low activities of neutral naphthyiamidases (marker substrate Leu-β-NA) and of acid carboxypeptidases (EC 3.4.16; marker substrate Z-Phe-Ala). The intracellular localisation of these peptidases and that of α-mannosidase (EC 3.2.1.24) was studied by subcellular fractionations in different media. In density gradient centrifugations in non-aqueous glycerol-potassium iodide media the alkaline peptidases remained mainly in the application zone …