Molecular Characterization of the Glycated Plasma Membrane Calcium Pump

We have previously demonstrated (Diabetes 39:707–711, 1990) that in vitro glycation of the red cell Ca2+ pump diminishes the Ca2+-ATPase activity of the enzyme up to 50%. Such effect is due to the reaction of glucose with lysine residues of the Ca2+ pump (Biochem. J. 293:369–375, 1993). The aim of t...

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Autores principales: González Flecha, F. L., Castello, Pablo R., Gagliardino, Juan José, Rossi, Juan Pablo F. C.
Formato: Articulo
Lenguaje:Inglés
Publicado: 1999
Materias:
Ciencias Naturales
Biología
PMCA
Glycation
Phosphatase
Lys residues
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/131051
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-131051
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Ciencias Naturales
Biología
PMCA
Glycation
Phosphatase
Lys residues
spellingShingle Ciencias Naturales
Biología
PMCA
Glycation
Phosphatase
Lys residues
González Flecha, F. L.
Castello, Pablo R.
Gagliardino, Juan José
Rossi, Juan Pablo F. C.
Molecular Characterization of the Glycated Plasma Membrane Calcium Pump
topic_facet Ciencias Naturales
Biología
PMCA
Glycation
Phosphatase
Lys residues
description We have previously demonstrated (Diabetes 39:707–711, 1990) that in vitro glycation of the red cell Ca2+ pump diminishes the Ca2+-ATPase activity of the enzyme up to 50%. Such effect is due to the reaction of glucose with lysine residues of the Ca2+ pump (Biochem. J. 293:369–375, 1993). The aim of this work was to determine whether the effect of glucose is due to a full inactivation of a fraction of the total population of Ca2+ pump, or to a partial inactivation of all the molecules. Glycation decreased the Vmax; for the ATPase activity leaving unaffected the apparent affinities for Ca2+, calmodulin or ATP. The apparent turnover was identical in both, the glycated and the native enzyme. Glycation decreased the Vmax; for the ATP-dependent but not for the calmodulin-activated phosphatase activities. Concomitantly with the inhibition, up to 6.5% of the lysine residues were randomly glycated. The probabilistic analysis of the relation between the enzyme activity and the fraction of nonmodified residues indicates that only one Lys residue is responsible for the inhibition. We suggest that glucose decreases the Ca2+-ATPase activity by reacting with one essential Lys residue probably located in the vicinity of the catalytic site, which results in the full inactivation of the enzyme. Thus, Ca2+-ATPase activity measured in erythrocyte membranes or purified enzyme preparations preincubated with glucose depends on the remaining enzyme molecules in which the essential Lys residue stays unglycated.
format Articulo
Articulo
author González Flecha, F. L.
Castello, Pablo R.
Gagliardino, Juan José
Rossi, Juan Pablo F. C.
author_facet González Flecha, F. L.
Castello, Pablo R.
Gagliardino, Juan José
Rossi, Juan Pablo F. C.
author_sort González Flecha, F. L.
title Molecular Characterization of the Glycated Plasma Membrane Calcium Pump
title_short Molecular Characterization of the Glycated Plasma Membrane Calcium Pump
title_full Molecular Characterization of the Glycated Plasma Membrane Calcium Pump
title_fullStr Molecular Characterization of the Glycated Plasma Membrane Calcium Pump
title_full_unstemmed Molecular Characterization of the Glycated Plasma Membrane Calcium Pump
title_sort molecular characterization of the glycated plasma membrane calcium pump
publishDate 1999
url http://sedici.unlp.edu.ar/handle/10915/131051
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AT gagliardinojuanjose molecularcharacterizationoftheglycatedplasmamembranecalciumpump
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