A kinetic model to explain the maximum in α-amylase activity measurements in the presence of small carbohydrates

✍ Scribed by Tim Baks; Anja E.M. Janssen; Remko M. Boom

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 290 KB
• Volume: 94
• Category: Article
• ISSN: 0006-3592
• DOI: 10.1002/bit.20779

✦ Synopsis

Abstract

The effect of the presence of several small carbohydrates on the measurement of the α‐amylase activity was determined over a broad concentration range. At low carbohydrate concentrations, a distinct maximum in the α‐amylase activity versus concentration curves was observed in several cases. At higher concentrations, all carbohydrates show a decreasing α‐amylase activity at increasing carbohydrate concentrations. A general kinetic model has been developed that can be used to describe and explain these phenomena. This model is based on the formation of a carbohydrate–enzyme complex that remains active. It is assumed that this complex is formed when a carbohydrate binds to α‐amylase without blocking the catalytic site and its surrounding subsites. Furthermore, the kinetic model incorporates substrate inhibition and substrate competition. Depending on the carbohydrate type and concentration, the measured α‐amylase activity can be 75% lower than the actual α‐amylase activity. The model that has been developed can be used to correct for these effects in order to obtain the actual amount of active enzyme. © 2006 Wiley Periodicals, Inc.