Substrate consumed

AX = amount of biomass produced AS = amount of substrate consumed... 

AS = the total amount of substrate consumed ASassunilation = amount of substrate assimilated... 

ASgrowth energy = amount of substrate consumed to provide energy for grwoth ASmaintenance energy = amount of substrate consumed to provide energy for maintenance... 

Substrate Consumption. Consumption of substrates and generation of products can be described using empirical yield coefficients. Yields are usually based on the amount of limiting substrate that has been consumed. Thus, Ypjs denotes the mass of product produced per mass of substrate consumed, and Yxts denotes... 

Velocity—rate, v, activity, d P ldl, —d[S /dt—is how fast an enzyme converts substrate to product, the amount of substrate consumed, or product formed per unit time. Units are micromoles per minute (pmol/min) = units. 

Mitochondria do three things oxidize substrates, consume oxygen, and make ATP. Uncouplers prevent the synthesis of ATP but do not inhibit oxygen consumption or substrate oxidation. Uncouplers work by destroying the pH gradient. The classic uncoupler is dinitrophenol (DNP). This phenol is a relatively strong acid and exists as the phenol and the phenolate anion. 

A 4 km intercepting sewer with diameter D = 0.5 m is flowing half full. The DO consumption rate, rf, of the sewer biofilm is measured, and an average value of 0.6 g02 m-2 h-1 was estimated. The biofilm yield constant of the heterotrophic biomass was not measured but was estimated as Yf= 0.55 gCOD biomass produced per gCOD substrate consumed. Only aerobic heterotrophic transformations in the biofilm are expected to proceed. 

The titrant used in pH-stat titration is usually a dilute (perhaps 0.01 M) acid or base. Two different sets of data can be obtained from a pH-stat titration. The amount of a substrate consumed or product formed can be determined by the total amount of titratant used. Because the titrant is added over a period of time, the rate of reaction can also be determined. 

Thus, the specific growth rate in a chemostat is controlled by the feed flow rate, since // is equal to D at steady state conditions. Since ft, the specific growth rate, is a function of the substrate concentration, and since fi is also determined by dilution rate, then the flow rate F also determines the outlet substrate concentration S. The last equation is, of course, simply a statement that the quantity of cells produced is proportional to the quantity of substrate consumed, as related by the yield factor Yx/s-... 

The yield (y) of a biomass production process is defined as the moles of biomass formed per mole of substrate consumed. Aerobic conditions are more conducive to higher biomass formation (and therefore also to biofilm formation) than anaerobic conditions. Empirically, under aerobic conditions, a yield of 0.05 - 0.6mol biomass/mol carbon can be obtained, while under anaerobic conditions the attainable yield falls to 0.04 -0.083mol. The reaction kinetics of biodegradation processes can be approximated by the first-order reaction rate constant k as follows ... 

The enzyme activity is usually reported in units of substrate consumed or product produced over a given period of time, at near-saturating concentration of substrate and at a given pH or temperature. For a pure enzyme, specific activity can be reported, for example, as jmol or mmol/ min per mg enzyme-protein. 

Langmuir surface area micropore volume ° average pore size d = AV JS by Langmuir TOFav = (moles of substrate consumed)/)(moles of M) x time] inside parentheses, the values for the... 

Provide a reference or direct experimental proof that the conditions chosen do provide initial rate measurements. At a minimum, the percentage of substrate consumed during the course of an initial rate determination should be specified. One should also show that under initial rate conditions a doubling of enzyme concentration should exactly produce a doubling in the observed initial rate. Likewise, if an auxiliary enzyme assay is used to monitor the primary enzyme s activity the observed rate at low or high substrate concentration should not depend on the concentration of additional enzyme(s), substrate(s), or factors used for the coupled assay. 2. Describe all assay conditions (eg., concentrations of substrates, products, inhibitors, and/or activators enzyme concentration temperature pH and buffer composition ... 

A parameter used in the study of the growth and cultivation of microorganisms. It is equal to the mass of the amount of microorganism produced divided by the mass of the substrate consumed. The term energy yield coefficient is used if the ratio represents the yield of ATP produced per the theoretically possible yield. 

The initial concentrations are 1.0 g/1 of the cells substrate. The yield is 0.6 g cells/g substrate consumed. 

Methods for assessing protein purity must quantitate the amount of target protein relative to the amount of contaminant(s) in the sample. This requires two separate analytical methods one for the taiget protein and one for the total protein including contaminants. For example, with enzymatic proteins, assessment of functional purity typically relies on kinetic assays in which the amount of substrate consumed or product produced per unit time is proportional to the amount of enzyme present. The total activity of the sample is calculated and compared to the total amount of protein to give the specific activity of the sample. Methods for determining total protein are discussed in Chapter Bl. An increase in specific activity at a purification step reflects a loss of contaminant proteins. 

Eq. (6.22) can be integrated if we know the relationship between Cs and Cx. It has been observed frequently that the amount of cell mass produced is proportional to the amount of a limiting substrate consumed. The growth yield (Yx/S) is defined as... 

Since many biochemical reactions and their stoichiometry are not well understood, we often find a more empirical approach to the quantitative assessment of the kinetics. Mass concentration units (e.g., g/L) are often used along with yield coefficients to calculate the distribution of products formed and the amount of substrate consumed. In the absence of any inhibition effects and in the presence of an infinite supply of substrate, the rate of cell growth rx is autocatalytic, that is, it depends only on the concentration of cells (Cx), and the more cells we have, the higher the growth rate. The cell biomass is typically represented by X ... 

Empirically determined yield factors are typically used to relate the mass of cells produced per unit mass of substrate consumed (7XS) and the mass of product generated per unit mass of biomass produced (IpX). 

The volumetric substrate consumption rates, Qs (g/[L h]), were based on grams of substrate consumed per liter of culture medium/h at designated times. The product volumetric production rate (productivity), Qp (g/[L h]), was based on grams of product produced per liter of culture medium/h at designated times. The product yield, Yp/s (g/g), was calculated as the amount of product formed per gram of designated consumed substrates. 

Enzyme kinetics are normally determined under steady-state, initial-rate conditions, which place several constraints on the incubation conditions. First, the amount of substrate should greatly exceed the enzyme concentration, and the consumption of substrate should be held to a minimum. Generally, the amount of substrate consumed should be held to less than 10%. This constraint ensures that accurate substrate concentration data are available for the kinetic analyses and minimizes the probability that product inhibition of the reaction will occur. This constraint can be problematic when the Km of the reaction is low, since the amount of product (10% of a low substrate concentration) may be below that needed for accurate product quantitation. One method to increase the substrate amount available is to use larger incubation volumes. For example, a 10-mL incubation has 10 times more substrate available than a 1-mL incubation. Another method is to increase the sensitivity of the assay, e.g., using mass spectral or radioisotope assays. When more than 10% of the substrate is consumed, the substrate concentration can be corrected via the integrated form of the rate equation (Dr. James Gillette, personal communication) ... 

The metabolism of the drug candidate is not measured under initial rate conditions. Prior to initiating reaction phenotyping studies, a pool of human liver microsomes should always be used to establish initial rate conditions (i.e., conditions under which metabolite formation is proportional to protein concentration and incubation time), and total amount of substrate consumed should be less than 10%. 

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