Hexokinase and not glycogen synthase controls the flux through the glycogen synthesis pathway in frog oocytes
Author
dc.contributor.author
Preller Simmons, Ana
es_CL
Author
dc.contributor.author
Wilson, Christian A. M.
es_CL
Author
dc.contributor.author
Quiroga Roger, Diego
es_CL
Author
dc.contributor.author
Ureta, Tito
Admission date
dc.date.accessioned
2014-01-14T19:07:19Z
Available date
dc.date.available
2014-01-14T19:07:19Z
Publication date
dc.date.issued
2013
Cita de ítem
dc.identifier.citation
FEBS Letters 587 (2013) 2825–2831
en_US
Identifier
dc.identifier.other
DOI: 10.1016/j.febslet.2013.06.037
Identifier
dc.identifier.uri
https://repositorio.uchile.cl/handle/2250/119691
General note
dc.description
Artículo de publicación ISI
en_US
Abstract
dc.description.abstract
Here we set out to evaluate the role of hexokinase and glycogen synthase in the control of glycogen
synthesis in vivo. We used metabolic control analysis (MCA) to determine the flux control coefficient
for each of the enzymes involved in the pathway. Acute microinjection experiments in frog oocytes
were specifically designed to change the endogenous activities of the enzymes, either by directly
injecting increasing amounts of a given enzyme (HK, PGM and UGPase) or by microinjection of a
positive allosteric effector (glc-6P for GS). Values of 0.61 ± 0.07, 0.19 ± 0.03, 0.13 ± 0.03, and
0.06 ± 0.08 were obtained for the flux control coefficients of hexokinase EC 2.7.1.1 (HK), phosphoglucomutase
EC 5.4.2.1 (PGM), UDPglucose pyrophosphorylase EC 2.7.7.9 (UGPase) and glycogen synthase
EC 2.4.1.11 (GS), respectively. These values satisfy the summation theorem since the sum of the
control coefficients for all the enzymes of the pathway is 0.87. The results show that, in frog oocytes,
glycogen synthesis through the direct pathway is under the control of hexokinase. Phosphoglucomutase
and UDPG-pyrophosphorylase have a modest influence, while the control exerted by glycogen
synthase is null.