Open AccessPotato Sucrose Synthetase: Purification, Properties, and Changes in Activity Associated With Maturation
Author(s) -
Russell Pressey
Publication year - 1969
Publication title -
plant physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.554
H-Index - 312
eISSN - 1532-2548
pISSN - 0032-0889
DOI - 10.1104/pp.44.5.759
Subject(s) - sucrose , cleavage (geology) , enzyme , chemistry , specific activity , biochemistry , reagent , biology , organic chemistry , paleontology , fracture (geology)
Sucrose synthetase activity is high in young potato tubers but decreases markedly during maturation. The activity decreases rapidly after the tubers are harvested and remains low regardless of storage temperature. This enzyme was purified 34-fold from freshly harvested immature potatoes. It catalyzes both cleavage and synthesis of sucrose but the 2 activities differ in a number of ways. The pH optima are 6.6 and 8.8 for sucrose cleavage and synthesis. respectively. Sucrose cleavage is activated 4-fold by mercaptoethanol and is inhibited by Mn(2+). In contrast, sucrose synthesis is activated only slightly by either mercaptoethanol or Mn(2+) alone but 2-fold in the presence of both reagents. However, it was not possible to resolve the 2 activities, their stabilities to partial thermal inactivation are identical, and their ratios are constant over a wide range of activities.