Characterization of cellulase complex of Streptomyces albaduncus

✍ Scribed by Dr. R. K. Harchand; S. Singh

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 699 KB
• Volume: 37
• Category: Article
• ISSN: 0233-111X
• DOI: 10.1002/jobm.3620370204

✦ Synopsis

Abstract

Exoglucanase and endoglucanase (glucanases) enzymes of S. albaduncus were found to be very stable, showing only 36% and 8% loss in activities respectively after 3 days of incubation at 50 °C. In contrast, β‐glucosidase was significantly less stable retaining only 22.30% activity after 30 min incubation at 40 °C. The glucanases manifested maximum stability in pH range of 5.5–6.0 whereas β‐glucosidase was completely stable over a broad pH range of 6.5–9.0. Both glucanases were enhanced by some cations whereas β‐glucosidase did not require any cation for activity. K~m~ values for crude exoglucanase, endoglucanase and β‐glucosidase were 40.00 mg/ml, 92.30 mg/ml and 1.714 mM with maximum reaction velocities (V~max~) of 0.606, 33.330 and 0.109 IU/mg of protein, respectively. The enzymes were subject to end‐product inhibition, with exo‐ and endo‐glucanases decreasing by 20% and 70% respectively, in the presence of 0.3% glucose. However, β‐glucosidase showed marked resistance to glucose inhibition, retaining 59% of residual activity even in the presence of 30% glucose in the reaction mixture. This characteristic may be advantageous in the commercial exploitation of enzyme system. An activation of β‐glucosidase at lower concentrations of glucose suggests competitive inhibition.