Adsorption of Carbon Dioxide on Proteins in the Supercritical Region

Inactivation of Enzymes in an Aqueous Solution by Micro-bubbles of Supercritical Carbon Dioxide

“…The adsorption of SC CO 2 to protein molecules has been confirmed by a gravimetric method. 19 ) A sharp peak was observed at just above the critical pressure on the adsorption isotherms for SC CO 2 with several proteins. The adsorption of SC CO 2 by dry protein molecules (water content of3.4-8.4wt%) would not be comparable to the absorption of SC CO 2 into enzymes in a solution.…”

Disruption of Microbial Cells by the Flash Discharge of High-pressure Carbon Dioxide

“…Water, proteins and polysaccharides in the microbial cells are assumed to be the main components of the CO 2 -absorber or adsorbent, and the quantity of q is given as a function of the pressure and temperature, which can be evaluated by using the data for CO 2 absorption into water 12 ) and CO 2 adsorption to several kinds of proteins 13) and polysaccharides. 14l Carbon dioxide absorbed into water is the greater part of q, unless the moisture content of the cells is extremely low.…”

Enzymatic reactions in supercritical CO2: carboxylation, asymmetric reduction and esterification

“…Ikushima explained the high enantioselectivity of lipase in a very limited pressure range at 304.1 K as resulting from interaction between CO 2 and enzyme molecules [39,40]. We also propose that the large change in density could significantly change the interaction of CO 2 and the enzyme by the formation of carbamates from CO 2 and the free amine groups on the surface of the enzyme [38], by CO 2 adsorption on the enzyme as reported in other proteins [95] and/or by CO 2 incorporation in the substrate-binding pocket of the enzyme as reported in the incorporation of organic molecules in enzymes [96,97]. These interactions may gradually change the conformation of the enzyme in response to pressure, resulting in a continuous change in enantioselectivity.…”