Activation Energy and Allosteric Inhibition of Reaction Catalyzed by Aspartate Transcarbamylase from Atlantic Cod ( Gadus morhua ) Ovary

• Published in: Journal of the Fisheries Research Board of Canada
• Main Authors: King, Deborah, Baker, Dwight L.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1975
• Subjects: General Medicine; atlantic cod; Gadus morhua
• Online Access: http://dx.doi.org/10.1139/f75-243; http://www.nrcresearchpress.com/doi/pdf/10.1139/f75-243

Aspartate transcarbamylase was precipitated from a 0.85% KCl extract of Atlantic cod (Gadus morhua) ovary by exhaustive dialysis. The extract contained a dialyzable, heat stable inhibitor, which when added to the reaction mixture at a concentration [Formula: see text] of that in the ovary, reduced the activity to 13% and changed the aspartate concentration vs. activity curve from hyperbolic to sigmoidal. The enzyme was also inhibited by some pyrimidine derivatives but less strongly. The activation energy of the reaction catalyzed was 13,700 cal/mol and was constant between 5 and 45 C.