Respiration maximum rate

In both intermediate and maximum rates of respiration, control is distributed between several different steps, including the activity of the adenine nucleotide translocator (Groen et al., 1983). It is now recognized that the idea of a simple rate-limiting step for a metabolic pathway is simplistic and that control is shared by all steps although to different extents (Kacserand Bums, 1978 Fell, 1992). Each step in a pathway has a flux control coefficient (FCC) defined as ... 

When in later years Krebs reviewed the major points which had to be established if the cycle was to be shown to be operative in cells, the obvious needs were to find the presence of the required enzymes and to detect their substrates. As the substrates are present in the cycle in catalytic amounts their accumulation required the use of inhibitors. Krebs also stressed that rates of oxidation of the individual substrates must be at least as fast as the established rates of oxygen uptake in vivo, an argument first used by Slator (1907) with reference to fermentation A postulated intermediate must be fermented at least as rapidly as glucose is. (See Holmes, 1991). This requirement did not always appear to be met. In the early 1950s there were reports that acetate was oxidized by fresh yeast appreciably more slowly than the overall rate of yeast respiration. It was soon observed that if acetone-dried or freeze-dried yeasts were used in place of fresh yeast, rates of acetate oxidation were increased more than enough to meet the criterion. Acetate could not penetrate fresh yeast cell walls sufficiently rapidly to maintain maximum rates of respiration. If the cell walls were disrupted by drying this limitation was overcome, i.e. if rates of reaction are to be... 

Here curve I corresponds to water formation at a maximum rate in the respiration process. Since H+ and e formation is the general process for conjugated processes, their synchronization mechanism may be presented by the following scheme ... 

The dissolved oxygen half saturation constant (Ks) for microbial respiration has been reported to be less than 0.1 mg/1. It was found to be related to cell size for many organisms tested. Aerobic metabolic activities should therefore proceed at maximum rates when the dissolved oxygen concentration is... 

Cumulative gross dark fixation, respiration, and calculated net dark CO2 fixation integrated from onset of dark period to maximum rate of gross dark fixation. 

First, all the individual stages which constitute the cycle have been demonstrated to occur in muscle tissue, and the rates at which the individual reactions can proceed are sufficient to account for the maximum rate of respiration. The occurrence of some of the reactions in muscle tissue, as already mentioned, has been known since 1911, when Batelli and Stern demonstrated the rapid oxidation of citrate, succinate, fuma-rate, and malate in frog muscle. In 1936 the work of Martiusand Knoop - revealed the mechanism of the conversion of citrate into succinate, and the last major step of the cycle was discovered in 1937, when the formation of citrate from oxalacetate and pyruvate was demonstrated. It was this reaction which made a series of reactions into a cyclic sequence and which linked the series of reactions leading from citrate to oxalacetate with carbohydrate metabolism. 

Certain environmental factors markedly influence the rate of respiration. It is well known, for instance, that most tissues respire very slowly at or close to 0°C and that with rise in temperature there is a steady rise in respiration rate until we reach the optimum temperature (temperature at which the maximum rate is recorded) somewhere between 30-40°C. Within the range 0-30°C the temperature coefficient may be fairly constant, and such temperature coefficients... 

Cheyne-Stokes respiration Pattern of breathing with gradual increase in depth and sometimes in rate to a maximum, followed by a decrease resulting in apnea. The cycles ordinarily are 30 seconds to 2 minutes in duration, with 5 to 30 seconds of apnea. 

The endpoint of concern is or is defined so that it is right censored , once it happens, it does not reoccur. Examples are death or a minimum or maximum value of an enzyme or physiologic function (such as respiration rate). 

The particulate iron(ni) maximum is deeper than that of the particulate Mn maximum. This reflects the lower energy yield of iron respiration and its fester rate of... 

Depth profiles from the eastern tropical North Pacific (Figure 24.8) show the effects of nitrogen metabolism under 02-deficient conditions. The thermocline is characterized by a sharp decline in O2 concentrations that coincides with increasing nitrate and phosphate concentrations. The oxycline is produced by the respiration of sinking POM under vertically stagnant conditions. Below the oxycline, in depths where O2 concentrations are suboxic, phosphate concentrations continue to increase, but at a slower rate. In contrast, nitrate concentrations decline and reach a mid-water minimum that coincides with a nitrite maximum. The latter is referred to as the secondary nitrite maximum. (At this site the primary nitrite maximum is located at 50 m.)... 

Respiration inhibition kinetics analysis (RIKA) involves the measurement of the effect of toxicants on the kinetics of biogenic substrate (e.g., butyric acid) removal by activated sludge microorganisms. The kinetic parameters studied are max> the maximum specific substrate removal rate (determined indirectly by measuring the maximum respiration rate), and Ks, the half-saturation coefficient [19]. The procedure consists of measuring with a respirometer the Monod kinetic parameters, Vinax and Ks, in the absence and in the presence of various concentrations of the inhibitory compound. 

Maximum Use Concentration (MUC) Also known as the Maximum Use Level or MUL. It is the maximum outside contaminant concenttation a respirator can adequately protect against. The MUC can be calculated from the following relation MUC = PF or FF x PEL (or other standard). The MUC is limited to a chemical cartridge s rated capacity. 

In biochemical processes the presence of substrates and products of both conjugated reactions in the matrix (i.e. in the same zone of the reaction system) allows finer control of their rates an increase of ADP concentration to some maximum intensifies respiration and, vice versa, ATP accumulation in sufficient amounts suppresses it. 

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