Submitted to: Plant Physiology
Publication Type: Abstract Only
Publication Acceptance Date: 7/15/2000
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: A subtilisin-like protease (SSLP) from developing soybean (Glycine max) seeds was partially purified and characterized. A cDNA encoding the protein was generated from mRNA of developing seeds. It has an open reading frame of 2310 bp and encodes a precursor protein of 770 amino acids (Mr = 82,694). Southern and northern blot analysis revealed that a small family of genes encoded SSLP, possibly by one gene expressed only during early seed development. SSLP is localized in the seed coat and is not immunologically detected in cotyledons or any other plant tissues tested. During maturation both a signal peptide and a pro-sequence are removed from the protease. Abundance of this protease in the seed coat could reflect its role as a defensive protein. Alternatively, SSLP may play a role in maturation of seed proteins. Size exclusion and hydrophobic chromatography of the total pool of glycosylated seed proteins permitted SSLP to be separated from the vacuolar-processing enzyme (VPE) involved in the maturation of 11S storage proteins. Activity towards an specific octapeptide that mimics the cleavage site of the glycinin polypeptide, was carried out by both SSLP and VPE. Whereas VPE correctly processed 11S storage proteins, SSLP produced three distinct fragments under the same conditions. Studies to further characterize the nature and function of this protease in the seed coat are in progress.