Comments on spectrofluorometric assay of angiotensin-converting enzyme activity in blood plasma of different species

1986 ◽  
Vol 51 (10) ◽  
pp. 2280-2284
Author(s):  
Assia C. Shisheva ◽  
Ognian C. Ikonomov ◽  
Luben M. Sirakov
Keyword(s):  
Blood Plasma ◽  
Hydrolytic Activity ◽  
Converting Enzyme ◽  
Rat Blood ◽  
Spectrofluorometric Determination ◽  
Ace Activity ◽  
Angiotension Converting Enzyme ◽  
Hydrolysis Of ◽  
Rabbit Blood Plasma

The activity of the angiotension -converting enzyme (ACE) in human, dog, rabbit, and rat blood plasma was assayed by spectrofluorometric determination of the product liberated by enzymatic cleavage (L-His-L-Leu). In parallel experiments the hydrolysis of L-His-L-Leu by blood plasma was examined. The hydrolytic activity of rat blood plasma was high and therefore lower values of ACE activity were obtained; the use of the spectrofluorometric assay with rat blood plasma is therefore problematic. By contrast, L-His-L-Leu was not degraded by human, dog, and rabbit blood plasma and the spectrofluorometric determination of this peptide can thus be used to advantage to assay the ACE activity of blood plasma samples of these species.

Renin, aldosterone, and converting enzyme during exercise and acute hypoxia in humans

1982 ◽  
Vol 52 (2) ◽  
pp. 320-323 ◽  
Author(s):  
J. S. Milledge ◽  
D. M. Catley
Keyword(s):  
Acute Hypoxia ◽  
Plasma Renin ◽  
Converting Enzyme ◽  
Angiotensin I ◽  
Plasma Aldosterone Concentration ◽  
Low Concentrations ◽  
Close Relationship ◽  
Ace Activity ◽  
Angiotension Converting Enzyme ◽  
Hormone Analysis

The possibility that hypoxia might inhibit the secretion of angiotension-converting enzyme (ACE) would explain the low concentrations of aldosterone reported in humans at high altitude. To observe the effect of such a reduction in ACE concentration on the plasma aldosterone concentration (PAC) four subjects performed mild exercise throughout a 2-h study so as to elevate their plasma renin activity (PRA). After the first 60 min breathing air they were switched to breathing 12.8% O2 (4,000 an altitude equivalent). Venous samples were taken at intervals for hormone analysis. Results showed the expected rise of PRA and PAC both tending toward a plateau after about 45 min. There was no significant change in ACE activity (F = 0.065). Hypoxia produced a further 50% rise in PRA but a fall in PAC and a 30% reduction in ACE activity. Angiotensin I concentrations closely followed PRA throughout (r = 0.984). These results indicate that during exercise acute hypoxia changes the usual close relationship between PAC and PRA by reducing ACE activity.

Effects of gas composition and pH on kinetics of lung angiotensin-converting enzyme

1987 ◽  
Vol 62 (3) ◽  
pp. 1216-1221 ◽  
Author(s):  
D. A. Rickaby ◽  
R. D. Bongard ◽  
M. J. Tristani ◽  
J. H. Linehan ◽  
C. A. Dawson
Keyword(s):  
Angiotensin Converting Enzyme ◽  
Surface Area ◽  
Ph Dependence ◽  
Gas Composition ◽  
Converting Enzyme ◽  
Hydrolysis Process ◽  
Hypoxic Vasoconstriction ◽  
Ace Activity ◽  
Kinetics Of ◽  
Hydrolysis Of

Given the pH dependence of enzymes in general and the potential importance of a blood and alveolar gas composition dependency on the interpretation of changes in the hydrolysis of angiotensin-converting enzyme (ACE) substrates by pulmonary endothelial ACE, we examined the influence of Pco2 and Po2 on the hydrolysis of a synthetic ACE substrate (benzoyl-phenylalanyl-alanyl-proline, BPAP) on passage through isolated rabbit lungs. Perfusate pH values of about 7.1, 7.4, and 7.9 were obtained by ventilating the lungs with gas containing different CO2 concentrations and Po2 values of approximately 110 and approximately 10 Torr were obtained by varying the concentration of O2 in the ventilating gas mixture. In the range studied neither acidosis nor alkalosis produced any significant changes in BPAP hydrolysis or in the kinetic parameters, Vmax and Km, for the hydrolysis process. On the other hand, a reduction in BPAP hydrolysis was detected when the Po2 was reduced from 110 to 10 Torr. The Vmax for BPAP hydrolysis by the lung was inversely correlated with the magnitude of the hypoxic vasoconstriction that occurred, suggesting that the reduced BPAP hydrolysis with hypoxia was due to the loss of perfused surface area due to the vasoconstriction. The results suggest that correlations between Pco2 and/or pH and whole-lung ACE activity that might occur in diseased lungs do not imply causalty. The hemodynamic consequences of changing Po2 (i.e., hypoxic vasoconstriction) may alter whole-organ ACE activity in the sense of changing the perfused surface area (i.e., the amount of ACE in contact with flowing perfusate).

scholarly journals Rat Serum Carboxylesterase Partly Hydrolyses Gamma-Butyrobetaine Esters

2009 ◽  
Vol 60 (2) ◽  
pp. 147-156 ◽  
Author(s):  
Lida Bagdonienė ◽  
Danutė Labeikytė ◽  
Ivars Kalviņš ◽  
Veronika Borutinskaitė ◽  
Aleksandrs Prokofjevs ◽  
...  
Keyword(s):  
Blood Serum ◽  
Esterase Activity ◽  
Colorimetric Determination ◽  
Reaction Products ◽  
Rat Serum ◽  
Rat Blood ◽  
Optical Absorbance ◽  
Hydrolysis Of ◽  
Related Compounds

Rat Serum Carboxylesterase Partly Hydrolyses Gamma-Butyrobetaine EstersAlthough described some time ago, gamma-butyrobetaine esters and related compounds have not gained much attention from researchers, and their physiological function remains obscure. Formerly we detected GBB-esterase enzymatic activity in rat blood serum using phenylated gamma-butyrobetaine as an artificial substrate of the enzyme and HPLC. The aim of the present work was to develop an assay that would enable spectrophotometric or colorimetric determination of the reaction products of GBB-esterase activity and to reveal individual proteins performing GBB-esterase activity in rat blood serum. For this purpose gamma-butyrobetaine 1-naphthyl ester was synthesised. Hydrolysis of this ester releases 1-naphthol, which increases the optical absorbance at 322 nm. We have shown that the enzymatic hydrolysis of GBB 1-naphthyl ester to 1-naphthol in rat blood serum is due to GBB-esterase activity. An attempt was done to purify the enzyme from rat blood serum. By combining DEAE Sepharose at pH 4.2 and affinity chromatography with procainamide we achieved a 68-fold enrichment of GBB-esterase activity in our preparations. Separation of fraction proteins in 2D protein electrophoresis with following mass-spectrometry indicated that GBB esterase activity in rat blood serum is performed in part by carboxylesterase.

scholarly journals Optimization of a method for the determination of a mustard gas biomarker in human blood plasma by liquid chromatography–mass spectrometry

2017 ◽  
Vol 1 (3) ◽  
pp. 7-17
Keyword(s):  
Blood Plasma ◽  
Human Blood ◽  
Standard Addition ◽  
Proteinase K ◽  
Human Blood Plasma ◽  
Mustard Gas ◽  
Liquid Chromatography Mass Spectrometry ◽  
Tandem Mass Spectrometric ◽  
Hydrolysis Of

A method for the determination of a mustard gas biomarker (an S-hydroxyethylthioethyl adduct with albumin) in blood plasma was optimized with the use of HPLC with tandem mass-spectrometric detection. This method is based on the hydrolysis of this adduct by the proteinase K enzyme with the formation of the following stable tripeptide with cysteine, proline, and phenylalanine: S-HETE-Cys-Pro-Phe. The detection limit of mustard gas in human blood plasma was 2 ng/ml. The approach proposed was tested in the analysis of human blood plasma samples by the standard addition technique and also within the framework of the first official biomedical test carried out by the Organization for the Prohibition of Chemical Weapons (OPCW) in 2016, and it exhibited a good accuracy, reproducibility, and specificity of determination.

Automated kinetic determination of angiotensin-converting enzyme in serum.

1984 ◽  
Vol 30 (6) ◽  
pp. 901-902 ◽  
Author(s):  
A Harjanne
Keyword(s):  
Angiotensin Converting Enzyme ◽  
Previous Method ◽  
Converting Enzyme ◽  
Kinetic Determination ◽  
Assay Time ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of

Abstract In this automated kinetic modification of a previous method (Anal Biochem 95: 540-548, 1979) for determining angiotensin-converting enzyme (EC 3.4.15.1), 3-(2- furylacryloyl )-L- phenylalanylglycylglycine is used as the substrate. The change in absorbance at 340 nm is used to monitor hydrolysis of the substrate. The rate of hydrolysis is roughly threefold greater than with previously reported substrates, so assay time and sensitivity are improved.

scholarly journals In-vivo measurement of coronary Angiotension-Converting Enzyme (ACE) activity in humans

2002 ◽  
Vol 39 ◽  
pp. 267
Author(s):  
Cezar Staniloae ◽  
Richard Gallo ◽  
Ihor Dyrda ◽  
Gilbert Gosselin ◽  
Jacques Lesperance ◽  
...  
Keyword(s):  
Converting Enzyme ◽  
In Vivo Measurement ◽  
Ace Activity ◽  
Angiotension Converting Enzyme

scholarly journals Tissue Angiotensin-Converting Enzyme in Patients With Various Clinical Forms of Psoriasis

2007 ◽  
Vol 7 (2) ◽  
pp. 103-106 ◽  
Author(s):  
Jasminko Huskić ◽  
Faruk Alendar
Keyword(s):  
Angiotensin Converting Enzyme ◽  
Therapeutic Effects ◽  
Converting Enzyme ◽  
Healthy Individuals ◽  
Clinical Forms ◽  
Before And After ◽  
Erythrodermic Psoriasis ◽  
Ace Activity ◽  
Tissue Angiotensin

Tissue angiotensin-converting enzyme (ACE) was measured in 60 patients with psoriasis and in 20 healthy individuals. According to clinical forms of psoriasis, patients were further divided into three groups: psoriasis with solitary lesions (n=20), psoriasis with multiple disseminated lesions (n=20) and erythrodermic psoriasis (n=20). The tissue ACE activity was determined before and after therapy, by the spectrophotometric method using hippuryl-l-his-tidyl-l-leucine as a substrate. The enzyme activity is expressed in units: 1 U corresponds to 1 nmol of hippuric acid released by hydrolysis of hippuryl-l-histidyl-l-leucine per minute and 50 mg of the tissue. Before therapy, tissue ACE activity was significantly increased in patients with psoriasis (4,14±0,34; X±SEM) in comparison to healthy individuals (1,86±0,16). The greatest increase in tissue ACE activity was observed in patients with erythrodermic psoriasis (4,72±0,65), followed by those with multiple disseminated lesions (4,24±0,63) and solitary psoriatic lesions (3,47±0,48). After therapy, serum ACE activity was significantly decreased in all clinical forms of the disease. Determination of tissue ACE activity might be a good nonspecific parameter for assessment therapeutic effects.

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