Specificity of antisera raised against synthetic peptide fragments of high M(r) glutenin subunits.

In an attempt to detect high M(r) glutenin subunits specifically by immunochemical means, antisera were produced against synthetic peptides corresponding to three N-terminal sequences and to two repetitive motifs of high M(r) glutenin subunits. The three N-terminal peptides, NT1, NT2 and NT3, differed by a single substitution at the sixth position and correspond, respectively, to the N-termini off Dx subunits, Ax and Ex subunits and By and Dy subunits. The anti-peptide sera did not cross react with gliadins or with low M(r) glutenin subunits, and differed in their ability to recognise high M(r) glutenin subunits. The antisera to the repetitive motifs recognised all high M(r) glutenin subunits, whereas the antisera to the N-terminal peptides detected only some of the subunits. The antiserum directed against the N-terminal peptide from Dx subunits detected these subunits specifically, whereas the antiserum directed against the N-terminal peptide corresponding to y type subunits did not react with the homologous subunits although it did react with Dx or Ex subunits. Antisera were also produced against internal sequences present in the N-terminal domain specific for x and for y-type subunits, but these antisera did not react with the cognate proteins. The failure of some anti-peptide sera to recognise the homologous high M(r) glutenin subunits may be due to differences in conformation between peptides and the corresponding regions in proteins. (C) 1996 Academic Press Limited