Novel isoforms of proteinaceous α-amylase inhibitor (α-AI) from seed extract of Albizia lebbeck

• Published in: Acta physiologiae plantarum 2013-03, Vol.35 (3), p.901-909
• Main Authors: Shaikh, Faiyaz K, Gadge, Prafull P, Shinde, Ashok A, Jaiwal, Bhimrao V, Shinde, Keshav D, Padul, Monohar V, Kachole, Manvendra S
• Format: Article
• Language: English
• Subjects: Agriculture; Albizia lebbeck; ammonium sulfate; Biomedical and Life Sciences; chymotrypsin; clinical trials; digestion; fractionation; glycemic index; humans; Life Sciences; Original Paper; pepsin; Plant Anatomy/Development; Plant Biochemistry; Plant Genetics and Genomics; Plant Pathology; Plant Physiology; polyacrylamide gel electrophoresis; proteolysis; seeds; size exclusion chromatography; starch; swine; temperature; trypsin
• ISSN: 0137-5881; 1861-1664
• DOI: 10.1007/s11738-012-1133-5

Proteinaceous inhibitors of digestive α-amylase occur naturally in leguminous seeds and find applications in agriculture and clinical studies. We have detected and isolated eight novel α-amylase inhibitor isoforms in the seed extract of Albizia lebbeck. They are designated as AL-αAI-1 to AL-αAI-8. These isoforms specifically inhibit human salivary α-amylase and porcine pancreatic α-amylase. The occurrence and profile of α-amylase inhibitor isoforms were revealed by 7 % native-PAGE containing 0.1 % starch. The apparent molecular weights of native bands of AL-αAIs were 97.4, 68.6, 61.0, 57.2, 56.0, 54.7, 51.1, and 47.7 kDa, respectively. Partial purification of potent α-amylase inhibitor was achieved using ammonium sulfate fractionation and gel filtration chromatography on G-100 Sephadex column followed by preparative gel electrophoresis. SDS-PAGE analysis of partially purified AL-αAI showed two polypeptide bands of ~35.8 and ~32.6 kDa. All these isoforms showed effective resistance to in vitro proteolysis by pepsin, trypsin, and chymotrypsin. These inhibitors are stable over a wide range of pH and temperature and have optimum activity at pH 7 and at 37 °C. The finding and information obtained in the present investigation about novel isoforms of α-amylase inhibitors from A. lebbeck could be important and may find applications in clinical studies to modulate starch digestion and glycemic index.