SUPPRESSION OF PHASEOLIN AND LECTIN IN SEEDS OF COMMON BEAN, PHASEOLUS-VULGARIS L - INCREASED ACCUMULATION OF 54 KDA POLYPEPTIDES IS NOT ASSOCIATED WITH HIGHER SEED METHIONINE CONCENTRATIONS

Suppression of phaseolin and lectin accumulation in common bean result ed in higher concentrations of bean seed polypeptides with apparent mo lecular weights of 54 kDa and from 70 to 84 kDa on SDS-polyacrylamide gel electrophoresis. Polypeptides of 54 and 56 kDa segregated as produ cts of different alleles. Genes for the 54/56 kDa bands and phaseolin were estimated to be 26.2 +/- 3.7 map units apart. The 54 kDa band phe notype manifested by SDS-PAGE consisted of from one to three polypepti des of 54 kDa MW on 2D gels, and the 56 kDa phenotype consisted of one polypeptide of 56 kDa plus two minor polypeptides of 54-54.5 kDa mole cular weight. The pK(I) of these polypeptides was approximately 5.25. The methionine content of the 54 kDa polypeptides of the cultivar Grea t Northern Star was 1.6 +/- 0.1 g/100 g protein, which was not statist ically different from the value (1.5 +/- 0.1%) obtained for phaseolin isolated by the same procedure. F2 seeds deficient for phaseolin and l ectin contained as much total N per g as wild-type seeds and were not shrunken, but contained 50% more free amino acids. F2 seeds from two o f the three populations contained from 8 to 13% less methionine per mg total N.