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Biological Research

Print version ISSN 0716-9760

Abstract

ANDRADE, Cherie; SEPULVEDA, Carolina; CARDEMIL, Emilio  and  JABALQUINTO, Ana M. The Role of Tyrosine 207 in the Reaction Catalyzed by Saccharomyces cerevisiae phosphoenolpyruvate carboxykinase. Biol. Res. [online]. 2010, vol.43, n.2, pp.191-195. ISSN 0716-9760.  http://dx.doi.org/10.4067/S0716-97602010000200007.

The functional signifcance of tyrosine 207 of Saccharomyces cerevisiae phosphoenolpyruvate carboxykinase was explored by examining the kinetic properties of the Tyr207Leu mutant. The variant enzyme retained the structural characteristics of the wild-type protein as indicated by circular dichroism, intrinsic fuorescence spectroscopy, and gel-exclusion chromatography. Kinetic analyses of the mutated variant showed a 15-fold increase in Km CO2, a 32fold decrease in Vmax, and a 6-fold decrease in Km for phosphoenolpyruvate. These results suggest that the hydroxyl group of Tyr 207 may polarize CO2 and oxaloacetate, thus facilitating the carboxylation/decarboxylation steps.

Keywords : Phosphoenolpyruvate carboxykinase; Saccharomyces cerevisiae; CO2 interaction.

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