Amino acid sequence analysis of bitter peptides from a soybean proglycininsubunit synthesized in Escherichia coli

The cDNA encoding A(1a)B(1b) proglycinin was expressed in E. coli, for the efficient isolation of a single peptide responsible for the bitterness. The 55-kD proglycinin was highly purified, hydrolyzed, and further purified th rough a series of chromatographic steps to yield fractions with the major b itter peptides. The most bitter-tasting fractions contained peptides with a verage molecular weights lower than 1,700 Da. An analysis of the amino acid sequences indicated that many small hitter peptides (<1,000 Da) are compos ed of uncharged polar amino acids as well as hydrophobic amino acids, with a charged residue often being present at either end. This suggests the invo lvement of a certain structural requirement in taste perception.