Some kinetic studies with alpha-amylase from Aspergillus oryzae

Zulfiqar, Shagufta (1973) Some kinetic studies with alpha-amylase from Aspergillus oryzae. MSc(R) thesis, University of Glasgow.

Abstract

The chemical constitution and structure of amylases and the kinetics of reactions catalyzed by amylases are reviewed. The kinetics of hydrolyses of maltotetraose and maltotetraitol catalyzed by the a-amylase from Aspergillus Oryzae (Taka-amylase A) were measured under controlled conditions. At low concentrations (2 x 10e-3 M) maltotetraose is split into two maltose molecules and maltotetraitol into maltose and maltitol, but at higher concentrations (20 x 10e-3 M) maltotetraose forms malto- triose along with maltose and a very little glucose is also formed, while maltotetraitol is split into maltose, maltitol and maltotritol. These were thought to arise from transglycosylation reactions. Because of these tranglycosylation reactions it was not possible to measure the Michaelis parameters kcat . and Km for the hydrolyses, but the second-order constants kcat/Km were measured at low concentrations of maltotetraose at several pHs while for maltotetraitol only at optimum pH. The rates for maltotetraose were about ten times greater than maltotetraitol measured under the same conditions at optimum pH. Attempts to study the active centre of a-amylase from A. oryzae by perturbation difference spectroscopy were made but no specific interaction of maltose with the enzyme could be observed.

• Item Type: Thesis (MSc(R))
• Qualification Level: Masters
• Keywords: Biochemistry.
• Subjects: Q Science > QR Microbiology
• Colleges/Schools: College of Science and Engineering > School of Chemistry
• Supervisor's Name: Supervisor, not known
• Date of Award: 1973
• Depositing User: Enlighten Team
• Unique ID: glathesis:1973-78709
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 30 Jan 2020 15:00
• Last Modified: 15 Apr 2020 16:14
• Thesis DOI: 10.5525/gla.thesis.78709
• URI: https://theses.gla.ac.uk/id/eprint/78709