Serum pseudo—cholinesterase

Annapurna, V., Senciall, I., Davis, A.J., Kutty, K.M. (1991). Relationship between serum pseudo cholinesterase and triglycerides in experimentally induced diabetes mellims in rats. Diabetologia 34 320. ... 

Serum pseudo-cholinesterase (referred to hereafter as serum cholinesterase) activities were determined from a five minute reaction period at room tenperature with a modification of the method of EUman et 2Q. ( ). Briefly, a 10 pi 2d.iguot of serum ves added to both a reference and sample cuvette ocxitaining 3.0 ml of 5,5-dithiobis-(2-nltrobenzoate) (DDO buffer (0.25 mM in ph 8.0, 0.1 M sodium phos te buffer) and mixed with a micro-stirring rod. Die reaction ves steurted in the sample cuvette by the addition of 20 pi of aoetylthiochollne iodide (78 nM) and stirred. The reference cuvette received 20 pi of distilled water in place of substrate. Absorbance was measured at 412 im over a five minute period and the rate calculated from the slope of the derived curve. 

Thus a distinction was provided between simple esterases, such as fiver esterase, which catalysed the hydrolysis of simple aliphatic esters but were ineffective towards choline esters. The term 1 cholinesterase was extended to other enzymes, present in blood sera and erythrocytes of other animals, including man, and in nervous tissue, which catalysed the hydrolysis of acetylcholine. It was assumed that only one enzyme was involved until Alles and Hawes2 found that the enzyme present in human erythrocytes readily catalysed the hydrolysis of acetylcholine, but was inactive towards butyrylcholine. Human-serum enzyme, on the other hand, hydrolyses butyrylcholine more rapidly than acetylcholine. The erythrocyte enzyme is sometimes called true cholinesterase, whereas the serum enzyme is sometimes called pseudo-cholinesterase. Stedman,3 however, prefers the names a-cholinesterase for the enzyme more active towards acetylcholine, and / -cholinesterase for the one preferentially hydrolysing butyrylcholine. Enzymes of the first type play a fundamental part in acetylcholine metabolism in vivo. The function of the second type in vivo is obscure. Not everyone agrees with the designation suggested by Stedman. It must also be stressed that enzymes of one type from different species are not always identical in every respect.4 Furthermore,... 

True and pseudo-cholinesterase. The above serum preparations contained both the true and pseudo- cholinesterases of Mendel and Rudney.1 The effect of di-isopropyl phosphorofluoridate on these components was examined separately by means of the specific substrates described by Mendel, Mundel and Rudney,2 using the titration method described above. Phosphorofluoridate (5 x 10 8m) gave an inhibition of 57 per cent of the activity towards 00045m acetylcholine, 30 per cent of the activity towards 0-0005 m acetyl-/ methyl-choline, and 40 per cent of that towards 0-005 m benzoylcholine, after incubating the enzyme with the poison for 5 min. Thus in these experiments there appeared to be no appreciable difference in sensitivity of the true and pseudo-cholinesterases of horse serum to phosphorofluoridates. 

Myers, D.K. (1952). Studies on cholinesterase - 7. Determination of the molar concentration of pseudo-cholinesterase in serum. Biochem. J. 51 303-11. 

It usually has an extemely transient duration of action by virtue of the fact that it imdeigoes rapid hydrolysis by the help of serum butyryl (pseudo) cholinesterases. However, a prolonged muscular... 

Myers, D. K. (1952). Competition of the alicsierasc in rat serum with the pseudo cholinesterase for diisopropyl fluo-rophosphonaie. Science 115, 568-570. 

There are at least two cholinesterases acetylcholinestarase (AChE), a specific cholinesterase hydrolyzing predominantly the choline esters and occurring in high concentrations in brain, nerve and red blood cells and the other, butyrylcholinesterase (BChE), a nonspecific ( pseudo ) cholinesterase, hydrolyzing other esters as well, and found in the blood, serum, pancreas and liver. These enzymes manifest maximum catalytic activity around neutral pH and at the low levels of acetylcholine. The hydrolysis reaction of acetylcholine catalyzed by AChE is shown below ... 

In this respect, the most important information has been obtained from the effect of pH changes on enzymic activity. In Fig. 2 the pH-activity curves are represented for true cholinesterase (from Torpedo marmorata) and pseudo-ChE (from human serum), with ACh as substrate. The two curves are not only similar to each other, but also to the curves, characteristic for other, unspecific esterases (37). For the correct interpretation of such curves, it is important to make sure that only the protein in the... 

Use Biochemical research, determination of phosphorus in insecticides and poisons. (2) Pseudo or nonspecific cholinesterase prepared from horse serum. This esterase hydrolyzes other esters, as well as choline esters. It occurs in blood serum, the pancreas, and the liver. 

According to inpatient records from St. Luke s Hospital, the most common laboratory finding related to sarin toxicity was a decrease in plasma cholinesterase (ChE) levels in 74% of patients. In patients with more severe toxicity, plasma ChE levels tended to be lower, but a more accurate indication of ChE inhibition is the measurement of erythrocyte ChE, as erythrocyte acetylcholinesterase (AChE) is considered "true ChE" and plasma ChE is "pseudo-ChE." However, erythrocyte ChE is not routinely measured, whereas plasma ChE is included in many clinical chemistry panels thus, it can be used as a simple index for ChE activity. In both the Matsumoto and Tokyo subway sarin attacks, plasma ChE served as a useful index of sarin exposure. In 92% of hospitalized patients, plasma ChE levels returned to normal on the following day. In addition, inpatient records from St. Luke s Hospital showed an elevated creatine phosphokinase and leukocytosis in 11% and 60% of patients, respectively. In severe cases such as the Matsumoto attack, hyperglycemia, ketonuria, and low serum triglycerides due to tire toxic effects of sarin on the adrenal medulla were observed (Yanagisawa et al, 2006). 

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