Cereal Chem 55:877 - 888.  |  VIEW ARTICLE
Relationship of Exoproteolytic and Endoproteolytic Activity to Storage Protein Hydrolysis in Germinating Durum and Hard Red Spring Wheat.

K. R. Preston, J. E. Dexter, and J. E. Kruger. Copyright 1978 by the American Association of Cereal Chemists, Inc. 

Changes in exoproteolytic and endoproteolytic activities, endosperm protein solubility fractions, and sulfo- salicylic acid-soluble amino acids and peptides were determined during the germination of durum and hard red spring (HRS) wheats. Only small increases in exoproteolytic activity occurred in the varieties tested. Significant increases in endoproteolytic activity, however, were found during germination, with earlier and larger increases occurring in the HRS wheat varieties. Comparison between proteolytic activities and changes in endosperm protein solubility fractions of selected varieties indicated that enhancement of endoproteolytic activity during germination was required for extensive storage protein hydrolysis. Increases in amino nitrogen were found to be due almost entirely to amino acids, with little change in peptide levels, indicating that sufficient levels of exoproteolytic enzymes were present in the ungerminated wheats to hydrolyze peptides produced by increasing levels of endoproteolytic activity.