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STUDIES ON PHYTIN. II. PRELIMINARY STUDY OF SOME BARLEY PHOSPHATASES
Author(s) -
Preece Professor I. A.,
Grav H. J.
Publication year - 1962
Publication title -
journal of the institute of brewing
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.523
H-Index - 51
eISSN - 2050-0416
pISSN - 0046-9750
DOI - 10.1002/j.2050-0416.1962.tb01850.x
Subject(s) - phytic acid , enzyme , phytase , substrate (aquarium) , pyrophosphate , chemistry , hydrolysis , phosphate , biochemistry , inositol , phosphatase , chromatography , biology , ecology , receptor
Of barley enzymes liberating free inorganic phosphate ( a ) from phytic acid and the lower inositol phosphates, and ( b ) from phenylphosphate and pyrophosphate, those concerned with ( a ) are distinct from those of ( b ), as evidenced by inactivation and adsorption characters. At low substrate concentration (<0.05%), the hydrolysis of phytic acid by barley enzymes is characterized by a slow start, with the rate of reaction accelerating till a linear phase is reached; ultimately the expected retardation sets in. This behaviour can be explained on the basis of release of inorganic phosphate from phytic acid by an enzyme or enzymic system highly susceptible to substrate concentration and a second enzyme or group of enzymes acting progressively on the product of the first action; since—up to the point of production of inositol—successive actions give products susceptible to further action, there will be over a prolonged period a steady build up in concentration of substrate for the second phase, the rate of which soon becomes limited by enzyme concentration. At initial phytic acid concentrations >0.05%, the reaction curves for the barley enzyme mixtures come to resemble those typical of single enzyme reactions.