POLYPEPTIDES OF ALOE-BARBADENSIS MILLER

Major polypeptide species of proteins have been identified and analyse d by sodium dodecyl sulphate polyacrylamide gel electrophoresis in fre sh extracts of the whole leaf, leaf gel, root and stalk portions of Al oe barbadensis Miller plants of immature, young and mature ages. Extra cts of the fresh Aloe plant portions were prepared by dissection, tiss ue disruption, differential centrifugation and gel filtration methods. Extracted plant portions analysed by separation electrophoresis were also assayed by biochemical and immunological techniques for the prese nce of lectin associated reactions, i.e. agglutination or mitogenicity . Results of the separation electrophoresis analysis of extracts prepa red from fresh whole leaves and leaf gel of mature Aloe barbadensis Mi ller plants revealed 23 identifiable different polypeptides. Molecular weights of these polypeptides, calculated from sets of molecular weig ht reference standards, ranged from 70 000 for the largest to 3000 for the smallest. Electrophoresis profiles of commercially processed and freshly processed Aloe barbadensis Miller and Aloe saponaria Haw leaf gel extracts revealed similar patterns for major peptides. Treatment o f mature whole Aloe leaf extracts with acidic and alkaline conditions revealed distinct changes in pH stability of ten peptides. Comparisons of separation electrophoresis profiles of fresh extracts of Aloe whol e leaves and of leaf gel portions revealed marked differences in both molecular weights and concentrations of peptides found in extracts fro m mature, young or immature plants. This report is the first to descri be the nature and types of polypeptides detected in extracts of whole leaf, leaf gel, stalk and root portions of immature, young and mature Aloe plants. Accordingly, information in this report may be of conside rable value in helping to identify and characterize Aloe substances pr esent during processing in extracts and in products.