Volume 39, Issue 2 pp. 148-154

Purification and Characterization of Cytosolic Glyceraldehyde-3-phosphate Dehydrogenase from the Dromedary Camel

Latifa FOURRAT

Latifa FOURRAT

Laboratoire de Physiologie et Génétique Moléculaire, Département de Biologie, Faculté des Sciences Aïn-Chock, Université Hassan-II., Casablanca, Morocco

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Abdelghani IDDAR

Abdelghani IDDAR

Centre National de l'Energie, des Sciences et des Techniques Nucléaires, Center d'Etudes Nucléaires de la Maâmora Rabat 10001, Morocco

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Abdelaziz SOUKRI

Corresponding Author

Abdelaziz SOUKRI

Laboratoire de Physiologie et Génétique Moléculaire, Département de Biologie, Faculté des Sciences Aïn-Chock, Université Hassan-II., Casablanca, Morocco

*Corresponding author: Tel, 212-22-230680/84; Fax, 212-22-230674; E-mail, [email protected]Search for more papers by this author
First published: 12 February 2007
Citations: 2

This work was supported by a grant from the “Programme Thématique d'Appui à la Recherche Scientifique-Morocco”

Abstract

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) (EC 1.2.1.12), a key enzyme of carbon metabolism, was purified and characterized to homogeneity from skeletal muscle of Camelus dromedarius. The protein was purified approximately 26.8 folds by conventional ammonium sulphate fractionation followed by Blue Sepharose CL-6B chromatography, and its physical and kinetic properties were investigated. The native protein is a homotetramer with an apparent molecular weight of approximately 146 kDa. Isoelectric focusing analysis showed the presence of only one GAPDH isoform with an isoelectric point of 7.2. The optimum pH of the purified enzyme was 7.8. Studies on the effect of temperature on enzyme activity revealed an optimal value of approximately 28–32 °C with activation energy of 4.9 kcal/mol. The apparent Km values for NAD+ and DL-glyceraldehyde-3-phophate were estimated to be 0.025±0.040 mM and 0.21±0.08 mM, respectively. The Vmax of the purified protein was estimated to be 52.7±5.9 U/mg. These kinetic parameter values were different from those described previously, reflecting protein differences between species.

Edited by Minghua XU

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