An easy and effective demonstration of enzyme stereospecificity and equilibrium thermodynamics.

Chelsea Herdman, Michael Dickman

Journal: Biochemistry and molecular biology education : a bimonthly publication of the International Union of Biochemistry and Molecular Biology 2012;39(5):341-3

PMID: 21948505

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Abstract

Enzyme stereospecificity and equilibrium thermodynamics can be demonstrated using the coupling of two amino acid derivatives by Thermoase C160. This protease will catalyze peptide bond formation between Z-L-AspOH and L-PheOMe to form the Aspartame precursor Z-L-Asp-L-PheOMe. Reaction completion manifests itself by precipitation of the product. As the product has almost zero solubility, the equilibrium favors condensation and thus a normally hydrolytic enzyme catalyzes the opposite reaction. Neither Z-D-AspOH with L-PheOMe nor Z-L-AspOH with D-PheOMe produces any visible product.

Address: Department of Experimental Sciences, Collège Universitaire de Saint-Boniface, Winnipeg, Manitoba, Canada R2H 0H7.

DOI: 10.1002/bmb.20516

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https://antibodies.cancer.gov/detail/CPTC-HLA-B-1

MeSH Terms: Aspartame, Catalysis, Catalytic Domain, Chemical Precipitation, Color, Hydrogen-Ion Concentration, Metalloendopeptidases, Molecular Structure, Peptide Hydrolases, Solubility, Solutions, Stereoisomerism, Substrate Specificity, Thermodynamics, Thermolysin, Time Factors