Enzymatic assay for

A solution of 2.25 g (25 mmol) of D-glyccraldehyde in 300 mL of water is combined with a solution of 20 mmol of dihydroxyacetonc phosphate (DIIAP) in 200 mL of water freshly adjusted to pH 6.8. The mixture is incubated with 100 U of L-rhamnulose 1-phosphate aldolase at r.t. for 24 h with monitoring of conversion by TLC (2-propanol/sat. ammonia/water 6 4 2) and by enzymatic assay for DHAP55. 

Shmeeda H, Even-Chen S, Honen R, Cohen R, Weintraub C, Barenholz Y. Enzymatic assays for quality control and pharmacokinetics of liposome formulations comparison with nonenzymatic conventional methodologies. Methods... 

H. Irth A microfluidic-based enzymatic assay for bioactivity screening combined with capillary liquid chromatography and mass spectrometry. Lab Chip 2005, 5,... 

The enzymatic colorimetric format is followed by the Penzyme test. This test is a qualitative enzymatic assay for rapid detection of -lactam residues in milk (28-30). The detection principle of the Penzyme test is based on measurement of the degree of inactivation of the enzyme oo-carboxypeptidase is involved in the synthesis of the bacterial cell wall by -lactam antibiotics. These residues bind specifically with the enzyme and inactivate it, thus interfering with bacterial cell wall formation. 

Reducing end-based enzymatic assays for PGase activity, 335-348 PL, interference by, 342-343 Refractive index... 

Reliable enzymatic assays for SeMet are not available as specific SeMet metabolizing enzymes have not been identified and enzymes such as glutamine transaminase react with Met equally as well as with SeMet (Blazon et al., 1994). However, with some enzymes reaction rates for SeMet and Met differ sufficiently to be of some use in SeMet analysis. For example, SeMet is a better substrate than Met for the a,y-elimination by i.-methionine y-lyase of Pseudomonas putida (Esaki et al., 1979). The adenosyl methionine transferase from rat liver reacts with L-SeMet at 51% of the rate with L-Met, and with the corresponding D-isomers at only 13 and 10% of the rate of L-Met (Pan and Tarver, 1967). Other adenosyl methionine transferases, such as that from yeast, react with SeMet more rapidly and with higher stereoselectivity than with Met, providing an indirect means for SeMet determination (Mudd and Cantoni, 1957 Sliwkowski, 1984 Uzar and Michaelis, 1994). 

VARIN, L., BARRON, D., IBRAHIM, R.K., Enzymatic assay for flavonoid sulfotransferase. Anal. Biochem., 1987,161,176-180. 

Enzymatic assays for aminopeptidases can also be based on the readouts described below, which are applied primarily for endopeptidases and carboxypeptidases. These readouts use peptide substrates that span from the non-primed to the primed side. 

Figure 18.12 Enzymatic assay for transketolase based on L-tyrosine release.

McCloskey, L. P. (1980).An improved enzymatic assay for acetate in juice and wine. Am. J. Enol. 

Cooke, R.D. (1978) An enzymatic assay for the total cyanide content of Cassava (Mani-hot esculenta).. Sci. Food Agric., 29, 345-52. 

By using an enzymatic assay for fumarate which detects the compound in the lower pmol range the kinetics of fumarate release after activation of sensory rhodopsin-II could be measured. The concentration of fumarate released from the protein-bound pool increased transiently after a blue light pulse. The kinetics correlate consistently... 

EN92 Demanet, C., Goedhuys, W., Haentjens, M., Huyghens, L., Blaton, V. and Gorus, F. (1992). Two automated fully enzymatic assays for lipase activity in serum compared Positive interference from post-heparin lipase activity. Clin. Chem. 38, 288-292. 

RNl I Nagel, R. (1991). A new enzymatic assay for creatinine in blood, serum and urine for the Reflotron system. Clin. Chem. 37, 962, Abstr. 249. 

When a substrate can be directly measured, the reason for using an enzymatic assay for its quantitation may not be immediately apparent. However, complex biological media matrices may contain a variety of species that interfere with the direct measurement of analyte concentration. For example, if the analyte absorbs in the visible (vis) or ultraviolet (UV) region, direct quantitation may result in erroneously high values if interfering species absorb at the measurement wavelength. An enzymatic method, on the other hand, can monitor the absorbance decrease that occurs as a result of the selective consumption of analyte by the enzyme, thus avoiding the spectral interference. 

Blomme B, Lheureux P, Gerlo E, Maes V. Cobas Mira S endpoint enzymatic assay for plasma formate. J Anal Toxicol 2001 25 77-9. 

Hullin DA An IgM paraprotein causing a falsely low result in an enzymatic assay for acetaminophen. Clin Chem 1999 45 155-6. (Letter). 

Mahly M, Lardet G, Vallon JJ. Automated Cobas Mira kinetic enzymatic assay for ethylene glycol applied to emergency situations. J Anal Toxicol 1994 18 269-71. 

Using the sialosides obtained, a 96-well plate based coupled enzymatic assay for high-throughput colorimetric screening of structures that can be recognized by different sialidases was developed (Scheme 7) (75). Briefly, individual sialosides are incubated with an appropriate amount of a certain sialidase and an excess amount of exogalactosidase or hexosaminidase. If the... 

Interestingly, all these compounds are inactive against mouse lAPs, therefore, unsuitable for studies of lAP function in mouse models. The objectives of the current studies were the identification of small-molecule modulators of mouse lAP and, potentially, identification of novel selective scaffolds of human lAP. To this end, we applied and optimized the chemiluminescent assays that were successfully utilized for screening human lAP, TNAP, and FLAP and developed a novel assay for mouse lAP, analogous to the assays of other isozymes. These assays utilize CDP-star, a substrate of alkaline phosphatases specifically invented for and commonly utilized in blotting techniques [19, 20]. Development and utilization of the prototype plate-reader enzymatic assay for TNAP isozyme with CDP-star substrate was previously described in detail elsewhere [21]. 

Thompson, M. B., P. C. Blair, R. W. Morris, D. A. Neptun, D. E Deyo, and J. A. Popp. 1987. Validation and application of a hquid-chromatographic/enzymatic assay for individual bile acids in the serum of rats. Clinical Chemistry 33 1856-1862. 

Again, there are several methods for measuring individual phospholipids enzymatic assays for total phospholipids provide a convenient starting point. Because most plasma phospholipids contain choline, the enzyme phospholipase-D is used to release choline from phospholipids. The choline is then oxidized by added choline oxidase to yield betaine and hydrogen peroxide, which are then measured using a peroxidase-linked colorimetric detection method. In cases of phospholipidosis, it is essential to use cells (e.g., leukocytes) to demonstrate the accumulation of phospholipids. 

The liver is the main origin of ketones in laboratory animals, where the long chain fatty acids are released from plasma albumin and bound to fatty acid-binding proteins in the hepatocytes. The long chain fatty acids react with CoA and then can be used to synthesize triacylglycerol or undergo beta-oxidation to acetyl CoA. When the levels of plasma fatty acids are elevated, acetyl CoA can be metabolized to form acetoacetate and 3-hydroxybutyrate or enter the tricarboxylic acid cycle. In ketosis, the levels of acetone, acetoacetate, and 3-hydroxybutyrate (also known as beta-hydroxybutyrate) are increased in both plasma and urine these three compounds historically were collectively called ketone bodies. Urine test strips can be used to test for ketonuria, and there are several enzymatic assays for 3-hydroxybutyrate and acetoacetate. 

Cavari, B. and Phelps, G., 1977. Sensitive enzymatic assay for glucose determination in natural waters. Appl. Environ. Microbiol., 33 1237—1243. 

Three decades elapsed between the first isolation of erythrocuprein and the discovery of a catalytic function for this protein. Attributable to the high interest in the biochemistry of reactive oxygen species, numerous enzymatic assays for superoxide dismutases were developed in the last years. Nevertheless, the original assay of McCord and Fridovich is still currently used for routine purposes The reactivity of super-... 

De Boer, A.R., Bruyneel, B., Krabbe, JG, Lingeman, H., Niessen, W.M.A., Irth, H., A microfluidic-based enzymatic assay for bioactivity screening combined with capillary liquid chromatography and mass spectrometry. Lab Chip, 5, 1286-1292, 2005. 

Microfluidic Systems for High-Throughput Screening, Fig. 8 Droplet-based microfluidic systems (a) droplets formed with microfluidic channels (an enzymatic assay for a single mast cell within a droplet. Hi. bright-fleld images ii., iv. fluorescence images [14]) and (b) in vitro evolution of proteins in a microfluidic channels... 

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