Fractionation, purification, and preliminary characterization of polygalacturonases produced by Aspergillus carbonarius

• Published in: Enzyme and microbial technology 1996, Vol.18 (1), p.59-65
• Main Authors: Anjana Devi, N., Appu Rao, A.G.
• Format: Article
• Language: English
• Subjects: Aspergillus carbonarius; Biological and medical sciences; Biotechnology; Enzyme engineering; Fundamental and applied biological sciences. Psychology; Growth, nutrition, metabolism, transports, enzymes. Molecular biology; Improved methods for extraction and purification of enzymes; Methods. Procedures. Technologies; Microbiology; Mycology; Polygalacturonase; purification
• ISSN: 0141-0229; 1879-0909
• DOI: 10.1016/0141-0229(96)00055-5

Multiple forms of polygalacturonases are produced by Aspergillus carbonarius. Three forms of this enzyme differing in molecular weights (PG I, 61,000; PG II, 42,000; and PG III, 47,000) and enzymatic properties have been isolated to apparent homogeneity by a simple method based on molecular sieve chromatography on Sephacryl S-200, ion exchange chromatography on CM Sephadex, followed by gel filtration on Sephadex G-50 superfine. All the three enzymes are endo-enzymes with high affinity for polygalacturonic acid. One of the forms, PG II, which accounts for >60% of the total polygalacturonases activity, had the highest reported specific activity of 7,000 U mg −1 protein. The three enzymes differ in their amino acid composition, affinity toward substrate, sensitivity toward metal ions, and thermal stability. The midpoint of thermal inactivation temperature ( T m) was 43,46, and 54°C for PG I, PG II, and PG III, respectively. The thermal inactivation of the multiple forms followed first-order kinetics with estimated half-lives of 6, 10, and 32 min, respectively.