INVESTIGADORES
IGLESIAS Alberto Alvaro
artículos
Título:
Ultrasensitive Glycogen Synthesis in Cyanobacteria
Autor/es:
D.F. GÓMEZ CASATI, M.A. AON Y A.A. IGLESIAS
Revista:
FEBS LETTERS
Editorial:
Springer-Verlag
Referencias:
Año: 1999 vol. 446 p. 117 - 121
ISSN:
0014-5793
Resumen:
AbstractCyanobacter ADPglucose pyrophosphorylase exhibitsa ultrasensitive response in activity towards its allostericeffector 3-phosphoglycerate, elicited by orthophosphate andpolyethyleneglycol-induced molecular crowding. The ultrasensitiveresponse was observed either when the enzyme operates inthe zero or first order region for its physiological substrates. Theultrasensitivity exhibited maximal amplification factors of 15^19-fold with respect to 1% of the maximal system velocity. Onlya 2.4^3.8-fold increase in 3PGA concentration was necessary toaugment the flux from 10% to 90% through AGPase ascompared with 200-fold required for the control. The resultsare discussed in terms of finely tuned regulatory mechanisms ofpolysaccharide synthesis in oxygenic photosynthetic organisms.z 1999 Federation of European Biochemical Societies.Key words: ADPglucose pyrophosphorylase; Glycogen andstarch biosynthesis; Enzyme regulation; Molecular crowding;Anabaena PCC 7120
