ARS | Publication request: Improved methods for high-throughput extraction of green barley malt and assay of endoproteinase activity allow examination of the properties and putative functions of the proteinases in barley populations

Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 29, 2007
Publication Date: July 11, 2007
Citation: Schmitt, M., Budde, A.D. 2007. Improved methods for high-throughput extraction of green barley malt and assay of endoproteinase activity allow examination of the properties and putative functions of the proteinases in barley populations. Cereal Chemistry. 84:313-319.

Interpretive Summary: Details on the roles that certain enzymes (called proteinases) play in converting the storage reserves (starch and protein) into smaller molecules that can support seedling growth, as well as supporting the growth of those microbes that are used to ferment beer, are poorly known. However, such details are important in order to allow plant breeders to develop barley varieties that provide an optimum balance of those nutrients to produce barley malt for brewing. The new methods presented in this publication provide a means for scientists to identify useful forms of these important enzymes in barley lines that are used as the base for developing new varieties that meet the needs of the malting and brewing industry. Use of these methods on current breeding lines of barley provides some new insights into how these enzymes work and ways in which they may be put to best use in the future.

Technical Abstract: We report efficient sample extraction and assay methods allowing determinations of activities from two mechanistic classes (cysteine and serine) of barley malt proteinase, and use the improved methods to assay > 2200 developmental lines of malting barley. The distributions of the resulting activities suggest differences in population structures between the two types of proteinases. Comparison of the activities of the green malt proteinases with standard malting quality measurements show significant correlations that differ between the proteinase types, suggesting different physiological roles for the two classes of proteinase in mobilization of barley seed protein and carbohydrate reserves.