Lactobacillus plantarum amylase acting on crude starch granules: Native isoforms and activity changes after limited proteolysis

• Published in: Applied biochemistry and biotechnology 2000, Vol.84 (1-9), p.721-730
• Main Authors: Florencio, J.A, Eiras-Stofella, D.R, Soccol, C.R, Raimbault, M, Guyot, J.P, Fontana, J.D
• Format: Article
• Language: English
• Subjects: alpha-amylase; Amylases - chemistry; Amylases - metabolism; Bacillus licheniformis; Bacteria; Biological and medical sciences; Biology of microorganisms of confirmed or potential industrial interest; Biomass; Biotechnology; Carbohydrate Metabolism; electrophoresis; Enzymatic activity; enzyme activity; Enzymes; Fermentation; Fundamental and applied biological sciences. Psychology; grains; heat tolerance; Hydrogen-Ion Concentration; Isoenzymes - chemistry; Isoenzymes - metabolism; Kinetics; Lactic Acid - metabolism; Lactobacillus - enzymology; Lactobacillus - growth & development; Lactobacillus plantarum; Microbiology; Miscellaneous; Mission oriented research; Peptide Fragments - metabolism; polypeptides; Pronase; proteolysis; scanning electron microscopy; Starch; Starch - metabolism; Starch - ultrastructure; starch granules; Triticum; Triticum aestivum; tubers; wheat starch
• ISSN: 0273-2289; 1559-0291
• DOI: 10.1385/ABAB:84-86:1-9:721

The microheterogeneous native amylolytic complex secreted by the isolate A6 of Lactobacillus plantarum revealed a selective enzyme specificity loss when submitted to a limited proteolysis under a suboptimum pH condition. A clear electrophoretic profile change toward just one shorter, more acidic, and equally active polypeptide fragment resulted from the pronase E pretreatment. Although the whole enzyme activity remained apparently unaffected for soluble starch, the native parallel activity on intact and non-gelatinized starch granules either from cereals or tubers was dramatically reduced. This phenomenon was more clearly documented by scanning electron microscopy using the easiest accessible native substrate: wheat starch granules. The anion-exchange-purified native enzymes from L. plantarum displayed a different optimum pH curve when compared with the thermotolerant alpha-amylase from Bacillus licheniformis. The alpha-amylases from the lactic-acid-producing A6 isolate presented an electrophoretic profile easily distinguishable from those from B. liqueniformis and B. subtilis species.