Lytic bodies from cereals hydrolysing maltose and starch

Abstract

Protein bodies and spherosomes from sorghum contained carbohydrase activity against maltose, starch and p-nitrophenyl-α- d-glucoside. Maltase activities in sorghum and also in maize lytic bodies were very high; carbohydrase activities of lytic bodies from whole wheat, whole barley, sorghum aleurone, sorghum embryo and maize embryo were considerably lower. The pH response of sorghum lytic bodies was bimodal with an optimum in the range of 3·4–4·2 and a minimum or a shoulder near pH 3·8. Protein bodies from sorghum, maize, wheat and barley reduced the iodine-colouring capacity of soluble starch to give a purple colour typical of a β-limit dextrin. With spherosomes colour reduction was usually more rapid, eventually taking the breakdown of starch beyond the achroic point. The lytic bodies produce both maltose and glucose from starch, except in the case of maize when only glucose was found. The data suggest that protein bodies contain a linked β-amylase-maltase system and that spherosomes contain a linked α-amylase-maltase system.