Potato Sucrose Synthetase: Purification, Properties, and Changes in Activity Associated With Maturation
AUTOR(ES)
Pressey, Russell
RESUMO
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 Mn2+. In contrast, sucrose synthesis is activated only slightly by either mercaptoethanol or Mn2+ 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.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=396157Documentos Relacionados
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