Premium
Ultrasensitive glycogen synthesis in Cyanobacteria
Author(s) -
Gómez Casati Diego F,
Aon Miguel A,
Iglesias Alberto A
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(99)00201-x
Subject(s) - allosteric regulation , biochemistry , chemistry , cyanobacteria , photosynthesis , effector , enzyme , glycogen , biophysics , biology , bacteria , genetics
Cyanobacter ADPglucose pyrophosphorylase exhibits a ultrasensitive response in activity towards its allosteric effector 3‐phosphoglycerate, elicited by orthophosphate and polyethyleneglycol‐induced molecular crowding. The ultrasensitive response was observed either when the enzyme operates in the zero or first order region for its physiological substrates. The ultrasensitivity exhibited maximal amplification factors of 15–19‐fold with respect to 1% of the maximal system velocity. Only a 2.4–3.8‐fold increase in 3PGA concentration was necessary to augment the flux from 10% to 90% through AGPase as compared with 200‐fold required for the control. The results are discussed in terms of finely tuned regulatory mechanisms of polysaccharide synthesis in oxygenic photosynthetic organisms.