Journal of cereal science vol:36 issue:2 pages:177-85
Four Secale cereale L. xylanase inhibitors (SCXI) from rye were purified to homogeneity. The inhibitor proteins all occur in two molecular forms, i.e. a c. 40 kDa monomeric protein and, presumably following proteolytic modification, a heterodimer consisting of two disulphide linked Subunits of c. 30 and c. 10 kDa. These basic proteins all have isoelectric points of at least 9 0 and a highly homologous N-terminal amino acid sequence. The isolated proteins strongly inhibited the activity of Aspergillus niger, Bacillus subtilis and Trichoderma viride family I I endoxylanases, but showed no activity towards an Aspergillus aculeatus family 10 endoxylanase. These characteristics demonstrate that rye contains a family of isoinhibitors with similar structures and specificities, that arc homologous with Triticum aestivum L xylanase inhibitor I (TAXI 1) from wheat and Hordeum vulgare L. xylanase inhibitor (HVXI) from barley. (C) 2002 Elsevier Science Ltd. All rights reserved.