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Studies on the Origin of Amylose and Amylopectin in Starch Granules. II. Changes in Amylose Content and Enzyme Activities in Cultures of Polytoma uvella
Author(s) -
Mangat B. S.,
Badenhuizen N. P.
Publication year - 1970
Publication title -
starch ‐ stärke
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.62
H-Index - 82
eISSN - 1521-379X
pISSN - 0038-9056
DOI - 10.1002/star.19700221002
Subject(s) - amylose , amylopectin , starch , chemistry , enzyme , food science , glycogen phosphorylase , biochemistry , polysaccharide , enzyme assay , transferase , glucosyltransferase
Changes in amylose percentage and the activities of starch‐synthesizing enzymes were followed in cultures of Polytoma uvella over a 6‐day period. Phosphorylase, ADPG‐glucosyltransferase, amylose content, ADPG and UDPG concentrations reached a peak in 96 hrs. old cultures. At this stage the cells of shaken cultures contained much higher enzyme activities and much more starch than those of stagnant cultures. After 96 hrs. phosphorylase and transferase activities declined sharply, amylose percentage decreased from 13.5 % to 6 %, but starch production continued, be it at a lower rate. Since Q‐enzyme activity increased during this period, it is suggested that the decrease in amylose percentage was due to preponderant production of amylopectin. A high correlation existed between amylose percentage and starchbound transferase. Experiments were initiated to bring about differential inactivation of phosphorylase and ADPG‐glucosyl‐transferase by growing cultures at higher temperatures.