ABSTRACT
The two (1→3 ), (1→4)-β-glucanase isoenzymes which participate in cell wall degradation in germinating barley represent the products of separate genes. At 2, 5 and 8 days after the initiation of germination in whole barley grain, mRNA was isolated from excised aleurone layers and scutella. The barley (1→3), (1→4)-β-glucanase isoenzymes therefore appear to represent a relatively simple, developmentally-regulated system for the study of tissue-specific regulation of gene expression and for the investigation of hormone action at a genetic level. The hormonal regulation of translatable mRNA encoding (1→3), (1→4)-β-glucanase appears to be similar to the regulation of mRNA for α-amylase in barley aleurone layers, for which gibberellic acid-enhancement is also blocked by abscisic acid. Purified (1→3), (1→4)-β-glucanase isoenzymes were hydrolysed with trypsin, resultant peptides were fractionated by reversed phase high performance liquid chromatography , and their NH2-terminal amino acid sequences were determined by automated Edraan degradation.
