cDNA cloning for a putative cysteine proteinase from developing seeds of soybean

cDNA clones for a putative cysteine proteinase were isolated from developing cotyledons of soybean (Glycine max.) using PCR-based techniques. The full-length clone of 1441 bp encodes a proteinase pre-propolypeptide of 380 amino acids. It belongs to the commonly known papain family and shows the highest sequence homology (up to 53% identity) to the protein 15A, a turgor-responsive cysteine proteinase of pea, as well as to several other stress inducible proteinases. Biosynthesis of the corresponding transcripts was shown to be developmentally controlled during embryogenesis. Southern analyses revealed occurrence of one to two genes in the soybean genome.