Carbon dioxide Michaelis-Menten

Biological. In activated sludge, <0.1% mineralized to carbon dioxide after 5 d (Freitag et al., 1985). The half-life of pentachlorobenzene in an anaerobic enrichment culture was 24 h (Beurskens et al., 1993). In an enrichment culture derived from a contaminated site in Bayou d lnde, LA, pentachlorobenzene underwent reductive dechlorination to 1,2,4,5- and 1,2,3,5-tetrachlorobenzene at relative molar yields of 9 and 91%, respectively. The maximum dechlorination rate, based on the recommended Michaelis-Menten model, was 131 nM/d (Pavlostathis and Prytula, 2000). 

In perchloric acid, hexoses and pentoses are oxidized by Ce(IV) via formation of two complex intermediates. The first is partly oxidized following Michaelis-Menten kinetics and partly dissociated to the second, which is oxidized more slowly than the former.180 The first step in the oxidation of aldoses by Tl(III) in the same medium involves the C-l-C-2 cleavage of the aldehydo form of the sugar. Thus, D-glucose gives D-arabinose and formic acid. With an excess of oxidant the final product is carbon dioxide.181 In the presence of a catalytic amount of sulfuric acid in acetic acid, Tl(III) oxidizes maltose and lactose to the corresponding disaccharide aldonic acids. The reaction showed activation enthalpies and enthropies characteristic of second-order reactions.182... 

The conversion of dissolved carbon dioxide in blood to HCO3 and H30 is catalyzed by the enzyme carbonic anhy-drase. The Michaelis-Menten constants for this enzyme and substrate are = 8 X 10 mol and k2 = 6 X 10 s. ... 

Figure 1. PBPK model for dX -trans-veimoic acid and its metabolites. Abbreviations are Dy intravenous dose (mg) Q or P or C, flow rate or partition coefficient or concentration (mg/1) subscripts c (cardiac), f (fat), g (gut), 1 (liver), pi (placenta), r (richly perfused tissues muscle, bone), s (slowly perfused tissues mammary gland, uterus), sk (skin) Dsc diffusivity in stratum comeum (cm%r) k rate constant subscripts b (biliary clearance), CO2 (side chain oxidation to carbon dioxide/hr), ct (cis/trans isomerization), tc (trans/cis isomerization) e (diffusion limited transfer between placenta and embryo, 1/hr) f (fecal excretion/hr) h (hydrolysis of glucuronide/hr) o (oral absorption) r (intestinal absorption) v (intravenous injection) K or V (affinity constant or maximum velocity where mg = apparent Michaelis-Menten glucuronidation constant and mx = apparent Michaelis-Menten oxidation constant). Rounded box indicates the submodels as diagrammed in Figures 2-5. (Reproduced with permission of Mosby-Year Book, Inc. from the American Academy of Dermatology. Clewell, [29].)...

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