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AMYLASE ENZYMES ISOLATED FROM INCUBATED DE‐EMBRYONATED MAIZE KERNELS
Author(s) -
GOLDSTEIN L. D.,
JENNINGS P. H.
Publication year - 1978
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1978.tb02629.x
Subject(s) - isoelectric focusing , chemistry , chromatography , amylase , isoelectric point , starch , enzyme , maltose , biochemistry
SUMMARY An enzyme extract prepared from incubated, de‐embryonated maize ( Zea mays L.) kernels was resolved into three major amylase activities by ion‐exchange chromatography using DEAE‐cellulose. These activities, designated peak I, II and III in order of their elution, were further analysed utilizing isoelectric focusing. The pi values of peaks I and II were found to be 4.55 and 4.95 respectively. The activity contained in peak III was separated into two isoelectric components with pI's of 4.30 and 5.05. Each of the four isoelectric forms showed distinct electrophoretic properties on polyacrylamide gels. Peak I contained (β‐amylase on the basis of its inactivation by 10 −5 M HgCl 2 , lack of protection against heat inactivation by added Ca 2+ , stable activity after dialysis against 10 −2 M EDTA, and its sole reaction product with starch being identified as maltose. Peak II activity appeared to be an a‐amylase as determined by its reaction products with starch and its stabilization against heat inactivation by added Ca 2+ , however, it was inactivated by HgCl 2 treatment and dialysis against EDTA. The two isoelectric components of peak III were also characterized as a‐amylase using the same criteria, with the 5.05 component being more sensitive to HgCl 2 inactivation than the 4.30 component. All four isoelectric forms exhibited broad pH activity profiles.