The Distribution of Acidic and Neutral Peptidases in Barley and Wheat Kernels

The activity of barley and wheat peptidases which hydrolyze alpha-N-benzoyl-dl-arginine-p-nitronnilide (BAPA) and alpha-N-benzoyl-l-arginine ethyl ester (BAEE) has been measured in proximal and distal portions of ungerminated grain and in these tissues during 6 and 7 day incubations. The proximal portion of ungerminated barleys contained the major part of both the acidic (BAPA-ase and acidic BAEE-ase) and neutral (neutral BAEE-ase) peptidases. In ungcrminated wheat these acidic and neutral peptidases were nearly evenly distributed between the proximal and dislal portions. Commercial wheat embryo was very high in acidic peptidase but contained no neutral peptidase. During the germination of both wheat and barleys, acidic and neutral peptidase activity in the seedlings increased with time. No such consistent increase was observed for aleurone and starchy endosperm tissue for any of these grains. Aleurone and starchy endosperm tissue incubated in the absence of the proximal portion of the kernel showed reduced peptidase activities.