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Kinetic modeling of the hydrolysis of sucrose by invertase
Author(s) -
Bowski L.,
Saini R.,
Ryu D. Y.,
Vieth W. R.
Publication year - 1971
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260130505
Subject(s) - invertase , sucrose , chemistry , substrate (aquarium) , fructose , hydrolysis , reaction rate , diffusion , chromatography , kinetics , analytical chemistry (journal) , biochemistry , catalysis , thermodynamics , oceanography , physics , quantum mechanics , geology
The kinetics of the enzymatic hydrolysis of sucrose by invertase have been examined, with particular emphasis on high substrate concentration. Initial rates of reaction were determined by following the production of glucose directly as a function of time over a wide range of substrate concentrations (0.04 M to 2.06 M ). The resulting data reveal a reaction rate that increases gradually until the sucrose concentration reaches about 0.29 M , after which the reaction velocity decreases with increasing sucrose concentration. Previous workers (e.g., Nelson and Schubert 1 ) have reported a peak reaction velocity as determined by indirect polarimetric measurements of glucose, at a sucrose concentration of about 0.17 M . These measurements, however, neglect the intermediate oligosaccharides formed by the transferase action of invertase, 8–10 and assume equal amounts of glucose and fructose. According to Anderson et al. , 10 these oligosaccharides interfere by producing an erroneously low reaction rate. Experimental results of this work confirm Anderson's observations, and show a further reaction rate increase of nearly 20% between sucrose concentrations of 0.177 M and 0.285 M under the same conditions of temperature, pH, and enzyme‐concentration. Effects of substrate diffusion, solution viscisity, water concentration, and substrate inhibition were experimentally studied and the results incorporated into a kinetic model that has proven satisfactory in modeling the experimental results. This model takes into account inhibition by primary substrate, with concentration of the secondary substrate water, as a rate limiting factor at sucrose concentrations greater than 0.285 M . The effects of the mixing, in terms of volumetric power input, on the relation rate have been tested. Approximately 40‐fold increase in volumetric power input caused on increase in the reaction rate. These experiments have shown that bulk mass transfer is not a rate limiting factor under the experimental conditions.