HETEROLOGOUS EXPRESSION AND DOUGH MIXING STUDIES OF WILD-TYPE AND MUTANT C-HORDEINS

Wild type and mutant (cysteine-containing) forms of C hordein were exp ressed in Escherichia coli. Incorporation of a mutant form with N-and C-terminal cysteine residues into dough using a 2g Mixograph showed si milar positive effects on dough strength to the incorporation of HMW s ubunit 1Bx7. Go-incorporation showed that the effects of the two prote ins were additive. In contrast, the incorporation of wild type C horde in or mutants with single cysteines at the N-or C-terminus resulted in decreased dough strength, with the two mutant forms inhibiting the po sitive effect of 1Bx7. Analysis of total protein extracts from the dou ghs indicate that the differences resulted from alterations in the pro portions of gluten monomers, small gluten polymers and large gluten po lymers. (C) 1998 Academic Press Limited.