Action of Sorghum Proteinase on the Protein Bodies of Sorghum Starchy Endosperm

Abstract

Protein bodies isolated from the starchy endosperm of ungerminated sorghum exhibited some autolytic activity but seemed incapable of significant self-hydrolysis. Enzyme assay, transmission electron microscopy, sodium dodecyl sulphate-polyacrylamide gel electrophoresis and amino acid analysis revealed that a proteinase extract from germinated sorghum could degrade the protein bodies in a manner resembling that which takes place in vivo. The protein bodies were degraded mainly from the periphery. Glutelin (matrix protein) was first hydrolysed, followed by the prolamin protein body protein. Proteinase extracts from both the germ and endosperm of germinated sorghum were capable of degrading the protein bodies. This finding is consistent with the concept that the proteinase is synthesized in the germ and then secreted into the starchy endosperm during germination.