Effect of alkaline pH on the activity and the structure of chloroplast fructose-1,6-bisphosphatase

The effect of alkaline pH on the stability of chloroplast fructose-1,6-bisphosphatase was examined. The incubation of the native enzyme (tetramer) at pH 8.9 lowered the specific activity (t0.5 = 6 min). The presence of fructose 1,6-bisphosphatase and Ca2+, two enzyme modulators, delayed the inactiva...

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Autores principales: Ballicora, M.A., Wolosiuk, R.A.
Formato: JOUR
Materias:
chloroplasts
enzyme dissociation
fructose-1,6-bisphosphatase
high pH
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_01689452_v70_n1_p35_Ballicora
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling todo:paper_01689452_v70_n1_p35_Ballicora2023-10-03T15:06:53Z Effect of alkaline pH on the activity and the structure of chloroplast fructose-1,6-bisphosphatase Ballicora, M.A. Wolosiuk, R.A. chloroplasts enzyme dissociation fructose-1,6-bisphosphatase high pH The effect of alkaline pH on the stability of chloroplast fructose-1,6-bisphosphatase was examined. The incubation of the native enzyme (tetramer) at pH 8.9 lowered the specific activity (t0.5 = 6 min). The presence of fructose 1,6-bisphosphatase and Ca2+, two enzyme modulators, delayed the inactivation process (t0.5 = 50 min) whereas sodium trichloroacetate, a chaotropic anion, accelerated it (t0.5 < 1 min). On the other hand, the conversion of 60% of the enzyme to dimers required an incubation of 3 h at pH 8.9. On this basis, it appeared that an inactive tetramer form preceded the dissociation of chloroplast fructose-1,6-bisphosphatase at pH 8.9; both fructose 1,6-bisphosphate and Ca2+ prevented enzyme inactivation by stabilizing the tetramer form. These results indicated that, in addition to their roles as enzyme modulators, sugar biphosphates and bivalent cations contribute to stabilizing the active conformation of chloroplast fructose-1,6-bisphosphatase. © 1990. Fil:Ballicora, M.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Wolosiuk, R.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_01689452_v70_n1_p35_Ballicora
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic chloroplasts
enzyme dissociation
fructose-1,6-bisphosphatase
high pH
spellingShingle chloroplasts
enzyme dissociation
fructose-1,6-bisphosphatase
high pH
Ballicora, M.A.
Wolosiuk, R.A.
Effect of alkaline pH on the activity and the structure of chloroplast fructose-1,6-bisphosphatase
topic_facet chloroplasts
enzyme dissociation
fructose-1,6-bisphosphatase
high pH
description The effect of alkaline pH on the stability of chloroplast fructose-1,6-bisphosphatase was examined. The incubation of the native enzyme (tetramer) at pH 8.9 lowered the specific activity (t0.5 = 6 min). The presence of fructose 1,6-bisphosphatase and Ca2+, two enzyme modulators, delayed the inactivation process (t0.5 = 50 min) whereas sodium trichloroacetate, a chaotropic anion, accelerated it (t0.5 < 1 min). On the other hand, the conversion of 60% of the enzyme to dimers required an incubation of 3 h at pH 8.9. On this basis, it appeared that an inactive tetramer form preceded the dissociation of chloroplast fructose-1,6-bisphosphatase at pH 8.9; both fructose 1,6-bisphosphate and Ca2+ prevented enzyme inactivation by stabilizing the tetramer form. These results indicated that, in addition to their roles as enzyme modulators, sugar biphosphates and bivalent cations contribute to stabilizing the active conformation of chloroplast fructose-1,6-bisphosphatase. © 1990.
format JOUR
author Ballicora, M.A.
Wolosiuk, R.A.
author_facet Ballicora, M.A.
Wolosiuk, R.A.
author_sort Ballicora, M.A.
title Effect of alkaline pH on the activity and the structure of chloroplast fructose-1,6-bisphosphatase
title_short Effect of alkaline pH on the activity and the structure of chloroplast fructose-1,6-bisphosphatase
title_full Effect of alkaline pH on the activity and the structure of chloroplast fructose-1,6-bisphosphatase
title_fullStr Effect of alkaline pH on the activity and the structure of chloroplast fructose-1,6-bisphosphatase
title_full_unstemmed Effect of alkaline pH on the activity and the structure of chloroplast fructose-1,6-bisphosphatase
title_sort effect of alkaline ph on the activity and the structure of chloroplast fructose-1,6-bisphosphatase
url http://hdl.handle.net/20.500.12110/paper_01689452_v70_n1_p35_Ballicora
work_keys_str_mv AT ballicorama effectofalkalinephontheactivityandthestructureofchloroplastfructose16bisphosphatase
AT wolosiukra effectofalkalinephontheactivityandthestructureofchloroplastfructose16bisphosphatase
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