Proteolysis in the subtropical woody tree Anadenanthera colubrina (Angico) seeds during and after germination

Abstract

Proteolysis of seed storage proteins (SSP) during germination provides a steady supply of amino acids to the embryo development into seedling. This process is coordinated by different peptidases that act sequentially and overlaid mode. These enzymes are an ancient group evolved separately in a wide structural and functional diversity and have many applications in medicine, pharmacy and industry. However, the knowledge about seed peptidases during germination was obtained from studies almost restricted to the cultivated species. This restriction implies caution about generalizations made from these studies, as well limits the biological knowledge about plant kingdom and technological use from plant peptidases. In this work, a scan of the proteolytic activity was held in germinating seeds of a leguminous subtropical woody tree. Eleven proteolytic activities were detected in protein extracts from embryonic axis and cotyledons. The presence and intensity of these activities varied over time and between these tissues. There was indication that aspartyl-endopeptidases (phytepsins) and cysteine-carboxypeptidases (plant cathepsins) were involved in A. colubrina SSP hydrolysis. These peptidases differ to that commonly involved in germination of the cultivated leguminous. In addition, one of detected phytepsins showed stability on pH scale, which is important for industrial uses. There was also detected a metallo-carboxypeptidase activity, which has been not described in plants. These peptidases must be isolated to confirm or not these indications. However, these data indicate the biological and technological importance of extending the studies about plant peptidases on a diverse genetic basis.