Molar < Stoichiometry

This bacterial enzyme, which is isolated from a methylotrophic bacterium, is of interest to flavin enzymologists in two respects. The first is the presence of an unusual covalently bound FMN moiety which has been identified as 6-S-cysteinyl FMN >and is present in a single molar stoichiometry with an Fe4/S4 cluster on the enzyme. In addition, it is the only known metalloflavoenzyme where the rate of molecular electron transfer between the two above redox centers is slow enough to be followed by kinetic techniques in the msec time range... 

Conceptually, assays for lipase activity using the colorimetric method (copper-soap procedure Basic Protocol 2) are similar to titrimetry in that liberated fatty acids are being measured however, the colorimetric method is more specific for fatty acids (Lowry and Tinsley, 1976). Quenched subsamples of emulsified acylglycerol/lipase reaction mixtures are combined with the biphasic mixture of cupric acetate/pyridine and benzene. Cupric salts of the fatty acids are formed (molar stoichiometry of fatty acid to Cu2+ of 4 2) and these soaps, which are blue in color, are partitioned into benzene to allow for quantification by measuring absorbance of the clear benzene phase at 715 nm. 

The minimum function gives the minimum value of (pXj/t>jMj) for all the reactants j taking part in this reaction. Finally, the reaction rate R is calculated as the product of the molar stoichiometry Uj of species i and the minimum of Rki and Rmi ... 

FABPs have been implicated in transmembrane and intracellular transport of fatty acids (Veerkamp et al., 1991 Storch and Thumser, 2000). These are a group of tissue-specific proteins of about 14-15 kDa that bind long-chain fatty acids (C16-C20) with high affinity and a molar stoichiometry of 1 1. Most bind unsaturated fatty acids with higher affinity than saturated fatty acids. In addition to transport functions it has been proposed that they modulate specific enzymes of lipid metabolism, regulate expression of fatty acid-responsive genes, maintain cellular membrane fatty acid levels, and reduce the concentration of fatty acids in the cell, thereby removing their inhibitory effect on metabolic processes. 

Figure 2 Chemical synthesis routes to riboflavin. In the upper part of the figure the laboratory route via W-(2-amino-4,5-dimethylphenyl)-D-1 -ribitylamine followed by Kuhn and Karrer is depicted. The lower part shows the technical route devised by Tishler using 3,4-dimethylaniline, o-ribose, benezenediazonium chloride, and barbituric acid. During the reaction of the azo compound with barbituric acid aniline is produced in molar stoichiometry.

The numerator of Equation 11.1 and Equation 11.2 includes the molar stoichiometry (Vsioic) of the metal atoms in the surface metal oxide (MO ) and its molecular weight (MJ. These equations differ in calculation of the denominator Equation 11.1 uses the surface area of the calcined, pure support oxide (no surface oxide), and Equation 11.2 uses the surface area of the calcined composite catalyst. Unless the support oxide shows negligible sintering and the support oxide content is low, ps rfi and psuj(2 are numerically different. 

The removal of residual chlorite from drinking water with iron(II) under slightly acidic conditions proved to be the best way. The molar stoichiometry, based on Eq. (8.43), predicts that 3.3 mg of Fe(II) would be required to completely reduce 1 mg chlorite [67]. 

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