Rate of sucrose

That the same enzyme,28 sucrose phosphorylase, is involved in the reaction of L-arabinose is indicated by the following observation. When L-arabinose is added to a mixture containing the enzyme, D-glucose-1-phosphate and D-fructose, of which the last is present in insufficient concentration to give the maximum rate of sucrose formation, an increase... 

Hydrolysis Rates of Sucrose, Raffinose and Stachyose by Purified Yeast ft-Frudofuranosidase... 

Despite the lack of visible necrosis of young and old leaves, it is possible to demonstrate alterations in cell permeability by following metabolite uptake after ozone exposure. If Acala SJ-1 cotton leaves are exposed to ozone and allowed to take up sucrose 2U hr later, there is nearly a doubling of the rate of sucrose uptake by leaves which are maximally susceptible to ozone. 

Figure 16.5. Supersaturation behavior, (a) Schematic plot of the Gibbs energy of a solid solute and solvent mixture at a fixed temperature. The true equilibrium compositions are given by points b and e, the limits of metastability by the inflection points c and d. For a salt-water system, point d virtually coincides with the 100% salt point e, with water contents of the order of 10-6 mol fraction with common salts, (b) Effects of supersaturation and temperature on the linear growth rate of sucrose crystals [data of Smythe (1967) analyzed by Ohara and Reid, 1973],...

Estimation of Catalytic Activity. The catalytic activities of the copolymers on the hydrolysis of polysaccharides were estimated, with the measurement of increase in reducing sugar in the reaction mixture with reaction time according to Somogyi method (22). The hydrolysis rates of sucrose were determined from the measurement of optical rotatory power... 

Rather than the solute speed in the phloem, we are sometimes more interested in how much matter is translocated. For example, if the sieve elements contain 0.5 m (500 mol m-3) sucrose moving at an average speed of 0.6 m hour-1, what is the transfer rate of sucrose in kg m-2 hour-1 By Equation 3.7 (Jj = vjcj), the flux density of sucrose is... 

Figure 11.6 Effect of permeate direction on reaction rate of sucrose Inversion (circles refer to membrane A and triangles to membrane B open symbols are associated with permeate flow from skin layer side and filled symbols from support layer side) [Nakajimactal., 1988]...

Bennett, M. C. Fentiman, Y. L., Growth Rate of Sucrose Crystals Related to Krypton Surface of Seeds. In Industrial Crystallization The Institute of Chemical Engineers London, U.K. 1969, pp. 217-226. 

Stefuca et al. (1990) proposed an ET method offering a rapid, convenient, and general approach to determine kinetic constants of immobilized biocatalysts. Here, a differential reactor (DR) was used for the measurement of the initial reaction rate of sucrose hydrolysis (Vallat et al. 1986). The enzyme column of the ET has been considered as a differential packed-bed reactor, and with a mathematical model, intrinsic kinetic constants of immobilized invertase were calculated from experimental DR and ET data. 

Q.29.9 You are asked to experimentally evaluate a new multi-stage microfluidic fuel cell in which a crude solution of cane sugar (sucrose) is first hydrolyzed by and acidic stage and then glucose and fructose diffuse into a second stage where electrochemical oxidation produces power. Propose a microscopic method to measure the rate of sucrose hydrolysis in the first stage. 

With an excess of invertase and GOD in the enzyme membrane the total rate of sucrose determination is limited by the spontaneous mutarotation. Therefore the sensitivity towards sucrose is only about 10% of that for glucose (Scheller and Karsten, 1983). Kinetic (dl/dt) measurement even gives only 1% of the glucose signal at the same sucrose concentration. Application of coimmobilized mutarotase gives rise to an increase of the sensitivity by a factor of 6 for stationary measurement... 

In acidic solution, the breakdown of sucrose into glucose and fructose has this rate law rate = A [H ][sucrose]. The initial rate of sucrose breakdown is measured in a solution that is 0.01 M... 

Fig. 2-3. Rate of sucrose hydrolysis by yeast sacchar-ase as a function of substrate concentration. Adapted from R. Kuhn in J. B. S. Haldane, "Enzymes," Longmans Greene and Co., London, 1930. Reprinted by permission of the Longman Group Limited.

To explain their results on the hydrolysis rate of sucrose to glucose and fructose by the enzyme invertase, Lenor Michaelis and Maud Men ten proposed, in 1913, the following scheme of reactions ... 

Rates of metabolism can be determined for each sugar from the experimental time period in which incorporation into insolubles is linear. Rates of metabolism determined in this way change with leaf development. The metabolism rate for both sugars increases during early development and then declines, however the rate of sucrose metabolism increases more than the rate of I -FS metabolism over the same developmental period. This indicates a changing relative contribution by the two sucrose metabolizing enzymes. 

The rate of carbon import and sucrose metabolism increased very rapidly during early development. Most of the increased rate of sucrose metabolism could be accounted for by a sharp rise in the flux through invertase. As the leaf became photosynthetically competent, the rate of utilization of carbon imported from mature leaves declined, however about one-half of sucrose metabolism remained through invertase. 

Figure 5. Oxidation rate of sucrose heptalinoleate vs. bodied linseed oil...

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