Invertase Invertase
is a yeast-derived enzyme. Invertase splits sucrose into glucose and fructose
(invert syrup) and can be applied for any inversion of sucrose especially liquefied
cherry centers, creams, mints, truffles, marshmallow, invert syrup and other fondants.
Invertase is used to improve shelf life of confections.
The official name
for invertase is beta-fructofuranosidase (EC3.2.1.26), which implies that the
reaction catalyzed by this enzyme is the hydrolysis of the terminal nonreducing
beta-fructofuranoside residues in beta-fructofuranosides. Note that alpha-D-glucosidase,
which splits off a terminal glucose unit, can also catalyze this reaction. Note
that sucrose can be hydrolyzed relatively easily; the reaction proceeds in an
acidic environment without the aid of invertase.
Invertase is mainly used
in the food (confectionery) industry where fructose is preferred over sucrose
because it is sweeter and does not crystallize as easily. However, the use of
invertase is rather limited because another enzyme, glucose isomerase, can be
used to convert glucose to fructose more inexpensively. For health and taste reasons,
its use in food industry requires that invertase be highly purified.
A
wide range of microorganisms produce invertase and can, thus, utilize sucrose
as a nutrient. Commercially, invertase is biosynthesized chiefly by yeast strains
of Saccharomyces cerevisiae or Saccharomyces carlsbergensis. Even within the same
yeast culture, invertase exists in more than one form. For example, the intracellular
invertase has a molecular weight of 135,000 Daltons, whereas the extracellular
variety has a molecular weight of 270,000 Daltons.
In contrary to most
other enzymes, invertase exhibits relatively high activity over a broad range
of pH (3.5--5.5), with the optimum near pH=4.5. The enzyme activity reaches a
maximum at about 55ºC. The Michaelis-Menten values of various enzymes vary
widely, but for most enzymes Km is between 2 mM and 5 mM. The Michaelis-Menten
value for the free enzyme is typically approx. 30 mm.
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