scholarly journals Human erythrocyte acetylcholinesterase in relation to cell age

1981 ◽  
Vol 195 (1) ◽  
pp. 221-228 ◽  
Author(s):  
D A Galbraith ◽  
D C Watts
Keyword(s):  
Enzyme Activity ◽  
Specific Activity ◽  
Kinetic Studies ◽  
Acetylcholinesterase Activity ◽  
Maximum Activity ◽  
Activity Profile ◽  
Cell Age ◽  
Cell Life ◽  
Adults And Children

Acetylcholinesterase was studied in human red cells that had been fractionated on Ficoll/Triosil density gradients into classes representing different ages in vivo. Reticulocytes have negligible acetylcholinesterase activity; this is rapidly acquired on maturation to the erythrocyte. The activity per cell reaches a maximum and then, after a constant period, declines again towards the end of cell life. The maximum activity and the rates of activity gain and loss per cell are quantitatively different in adults and children. Kinetic studies showed that Vmax. follows the same age/activity profile but Km is unaffected by cell age. The acetylcholinesterase protein content, determined by quantitative crossed immunoelectrophoresis, also shows a profile of increase and then decrease with cell age but the specific activity calculated from the protein estimate shows a reverse picture in which there is a slight decrease from young to mid-age cells followed by an increase again in older cells. These results are interpreted to indicate a complex developmental picture in which the overall cell age against enzyme activity profile is determined partly by the amount of enzyme protein present and partly from the modifying effect on the enzyme activity, of interactions with an aging cell membrane.

scholarly journals Study of Extraction and Enzymatic Properties of Cell-Envelope Proteinases from a Novel Wild Lactobacillus plantarum LP69

Catalysts ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 325 ◽  
Author(s):  
He Chen ◽  
Jie Huang ◽  
Binyun Cao ◽  
Li Chen ◽  
Na Song ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Lactobacillus Plantarum ◽  
Industrial Development ◽  
Extraction Efficiency ◽  
Specific Activity ◽  
Cell Envelope ◽  
Serine Proteinase ◽  
Kinetic Studies ◽  
Predicted Values ◽  
Hydrolyze Whey Protein

Lactobacilli cell-envelope proteinases (CEPs) have been widely used in the development of new streams of blockbuster nutraceuticals because of numerous biopharmaceutical potentials; thus, the development of viable methods for CEP extraction and the improvement of extraction efficiency will promote their full-scale application. In this study, CEP from a novel wild Lactobacillus plantarum LP69 was released from cells by incubating in calcium-free buffer. The extraction conditions of CEP were optimized by response surface methodology with the enzyme activity and specific activity as the detective marker. The optimal extraction conditions were: time of 80 min, temperature of 39 °C and buffer pH of 6.5. Under these conditions, enzyme activity and specific activity were (23.94 ± 0.86) U/mL and (1.37 ± 0.03) U/mg, respectively, which were well matched with the predicted values (22.12 U/mL and 1.36 U/mg). Optimal activity of the crude CEP occurred at pH 8.0 and 40 °C. It is a metallopeptidase, activated by Ca2+, inhibited by Zn2+ and ethylene-diamine-tetra-acetic acid, and a serine proteinase which is inhibited by phenylmethylsulfonyl fluoride. Kinetic studies showed that CEP from LP69 could hydrolyze whey protein, lactoglobulin and casein. Our study improves the extraction efficiency of CEPs from LP69, providing the reference for their industrial development.

scholarly journals Hereditary Nonspherocytic Hemolysis With Erythrocyte Phosphofructokinase Deficiency

Blood ◽  
1972 ◽  
Vol 39 (3) ◽  
pp. 415-425 ◽  
Author(s):  
Larry Waterbury ◽  
Eugene P. Frenkel
Keyword(s):  
Enzyme Activity ◽  
Adenosine Triphosphate ◽  
Lactate Production ◽  
Kinetic Studies ◽  
Glycogen Storage ◽  
Muscle Disease ◽  
Phosphofructokinase Activity ◽  
Phosphofructokinase Deficiency

Abstract Hereditary nonspherocytic hemolysis associated with abnormal erythrocyte phosphofructokinase activity was demonstrated in a young man. Enzyme activity in the propositus, his mother, and maternal grandmother was approximately 60% of normal controls. There was markedly increased lability of enzyme activity on in vitro storage. Kinetic studies revealed increased sensitivity to adenosine triphosphate inhibition. Erythrocyte adenosine triphosphate levels were depressed. The absence of muscle disease and the presence of normal in vivo lactate production following ischemic exercise differentiated this kindred from those with Type VII glycogen storage disease.

Calcium Determinations in Kinetic Studies

1967 ◽  
Vol 13 (9) ◽  
pp. 760-768 ◽  
Author(s):  
Joan Harrison ◽  
A J W Hitchman ◽  
J M Finlay
Keyword(s):  
Specific Activity ◽  
Kinetic Studies ◽  
Accurate Method ◽  
Urine Calcium ◽  
Blood Calcium ◽  
Exchangeable Calcium ◽  
Published Evidence ◽  
Activity Measurements

Abstract Published reports of a fraction of blood calcium that does not equilibrate with a tracer has created a controversy that challenges the validity of much calcium kinetic data. To resolve this controversy, calcium specific-activity measurements were made on blood and urine samples in vitro and in vivo. The experiments were designed to provide maximal sensitivity for demonstrating non exchangeable calcium. A new and accurate method for urine calcium determinations was used. The results demonstrated complete equilibration between tracer and stable blood calcium. We suggest that published evidence of non exchangeable calcium in blood and urine is erroneous due to inaccurate urine calcium determinations.

scholarly journals Solubilization of a mannose-polymerizing enzyme from Phaseolus aureus

1972 ◽  
Vol 128 (2) ◽  
pp. 243-252 ◽  
Author(s):  
J. S. Heller ◽  
C. L. Villemez
Keyword(s):  
Enzyme Activity ◽  
Enzyme Preparation ◽  
Specific Activity ◽  
Kinetic Studies ◽  
Competitive Inhibitor ◽  
Soluble Enzyme ◽  
Phaseolus Aureus ◽  
Original Activity ◽  
Solubilized Enzyme ◽  
High Concentrations

A soluble enzyme preparation, which catalyses the polymerization of mannose, was obtained by Triton X-100 extraction of a particulate fraction derived from Phaseolus aureus hypocotyls. The product that resulted when GDP-α-d-mannose was used as a substrate was a β-(1→4)-linked mannan, about three-quarters of which was alkali-insoluble. The mannose-polymerizing enzyme activity was at least as great in the soluble preparation as in the particulate preparation, and the specific activity of the solubilized enzyme was greater by a factor of at least 3.5. Kinetic studies of the soluble enzyme indicate that the apparent Km is 55–62μm, and a disproportionate increase in rate is observed at high concentrations. GDP-α-d-glucose is a strong competitive inhibitor of the mannose-polymerizing reaction, with an apparent Ki of 6.2μm. The soluble enzyme is relatively unstable, losing about two-thirds of its original activity in 5h at 0°C or in 24h at −20°C. A solvent (acetone, butanol, diethyl ether)-extracted particulate preparation, which also exhibits the same enzyme activity, is more stable, retaining full activity for at least 5 days at −20°C. There was no polymerizing-enzyme activity in the soluble enzyme preparation when UDP-d-glucose, UDP-d-galactose, UDP-d-xylose, UDP-l-arabinose or UDP-d-glucuronic acid were used as substrates. However, the soluble enzyme preparation would catalyse the polymerization of glucose, with GDP-d-glucose as substrate.

INFLUENCE OF ANDROGENS ON THE WEIGHTS OF THE MALE ACCESSORY REPRODUCTIVE ORGANS AND ON THE ACTIVITIES OF MITOCHONDRIAL ENZYMES IN THE EPIDIDYMIS OF THE RAT

1979 ◽  
Vol 82 (2) ◽  
pp. 293-303 ◽  
Author(s):  
D. E. BROOKS
Keyword(s):  
Enzyme Activity ◽  
Steady State ◽  
Specific Activity ◽  
Reproductive Organs ◽  
Maximum Activity ◽  
Rate Of Change ◽  
Mitochondrial Enzymes ◽  
Tissue Weight ◽  
Accessory Glands ◽  
Cauda Epididymidis

SUMMARY The influence of androgens on the male accessory glands of the rat was assessed in terms of changes in weight and of the specific activity of the mitochondrial enzymes, succinate dehydrogenase, glycerolphosphate dehydrogenase and pyruvate carboxylase, in the epididymis. In some instances, the activity of the cytoplasmic enzymes, hexokinase and phosphofructokinase, was also measured and the influence of androgens on these enzymes was found to be similar to that on the mitochondrial enzymes. After the administration of androgen to castrated rats the specific activity of enzymes reached a new steady state sooner than did epididymal weight. The time taken for the specific activity of the enzymes to reach a new steady state after the removal of androgen was variable, depending on the enzyme and the region of the epididymis. This time was generally longer, however, than the time taken for induction, and in the case of glycerolphosphate dehydrogenase, the decline of activity was slower in the cauda than in the caput. In castrated animals, about 100 times as much androgen was required to attain maximum tissue weight as was required to attain maximum enzyme activity. The epididymis, prostate and seminal vesicles responded similarly to androgen in terms of the dose–response pattern and the time taken for tissue weight to attain a new steady-state value, although the gain in weight of the epididymis relative to its weight in unstimulated control animals was less than the relative gain of the other accessory glands. Enzymes in the cauda epididymidis required lower amounts of androgen to elicit maximum activity than were required by those in the caput. The rate of change in the accessory glands in attaining new steady-state levels of tissue weight and enzyme activity was independent of the dose of androgen except during the first few days of hormone administration. Androgens were the most effective steroids in stimulating an increase of tissue weight and enzyme activity, although some changes were induced by oestradiol-3-benzoate and progesterone.

scholarly journals A major role for noncoding regulatory mutations in the evolution of enzyme activity

2019 ◽  
Vol 116 (25) ◽  
pp. 12383-12389 ◽  
Author(s):  
David W. Loehlin ◽  
Jesse R. Ames ◽  
Kathy Vaccaro ◽  
Sean B. Carroll
Keyword(s):  
Enzyme Activity ◽  
Specific Activity ◽  
Functional Divergence ◽  
Primary Source ◽  
Protein Activity ◽  
Genetic Changes ◽  
Gene Enhancer ◽  
Ethanol Toxicity ◽  
Regulatory Mutations

The quantitative evolution of protein activity is a common phenomenon, yet we know little about any general mechanistic tendencies that underlie it. For example, an increase (or decrease) in enzyme activity may evolve from changes in protein sequence that alter specific activity, or from changes in gene expression that alter the amount of protein produced. The latter in turn could arise via mutations that affect gene transcription, posttranscriptional processes, or copy number. Here, to determine the types of genetic changes underlying the quantitative evolution of protein activity, we dissected the basis of ecologically relevant differences in Alcohol dehydrogenase (Adh) enzyme activity between and within several Drosophila species. By using recombinant Adh transgenes to map the functional divergence of ADH enzyme activity in vivo, we find that amino acid substitutions explain only a minority (0 to 25%) of between- and within-species differences in enzyme activity. Instead, noncoding substitutions that occur across many parts of the gene (enhancer, promoter, and 5′ and 3′ untranslated regions) account for the majority of activity differences. Surprisingly, one substitution in a transcriptional Initiator element has occurred in parallel in two species, indicating that core promoters can be an important natural source of the tuning of gene activity. Furthermore, we show that both regulatory and coding substitutions contribute to fitness (resistance to ethanol toxicity). Although qualitative changes in protein specificity necessarily derive from coding mutations, these results suggest that regulatory mutations may be the primary source of quantitative changes in protein activity, a possibility overlooked in most analyses of protein evolution.

Synaptosomal Na+,K+-ATPase as a membrane probe in studying the in vivo action of morphine

1981 ◽  
Vol 59 (8) ◽  
pp. 687-692 ◽  
Author(s):  
Ophelia Wan-Kan ◽  
E. A. Hosein
Keyword(s):  
Activation Energy ◽  
Enzyme Activity ◽  
Transition Temperature ◽  
Specific Activity ◽  
Membrane Phospholipids ◽  
Membrane Probe ◽  
Biphasic Effect ◽  
Brain Synaptosomes ◽  
Membrane Bound

The activity of membrane-bound Na+,K+-ATPase was used as a metabolic probe to study the effects of morphine in vivo in rat brain synaptosomes. Arrhenius plots were generated to study an induced perturbation within the membrane. In acute studies 0.5-h postmorphine, the drug was without effect on the basal activity of the enzyme. With dopamine-stimulated Na+,K+-ATPase morphine decreased the apparent transition temperature and specific activity of the enzyme while there was a slight stimulation in its activation energy. An increase in these parameters was observed in samples taken from animals withdrawn from the drug for 48 h. These results strongly suggest the possible involvement of the membrane phospholipids as transducer which mediates the observed biphasic effect of the drug on enzyme activity.

Process Improvisation Strategies for the Enhancement of Lipase Activity

2021 ◽  
Vol 16 (7) ◽  
pp. 114-121
Author(s):  
Prama Das ◽  
Soham Chattopadhyay
Keyword(s):  
Response Surface Methodology ◽  
Enzyme Activity ◽  
Olive Oil ◽  
Specific Activity ◽  
Lipase Production ◽  
Maximum Activity ◽  
Statistical Optimization ◽  
Production Medium ◽  
High Enzyme ◽  
High Enzyme Activity

In this present study, lipase-producing bacteria were isolated and screened from an indigenous soil sample and were used for lipase production with high enzyme activity. In the production medium, different production media were screened and lipase production was induced by olive oil, 14 mL/L. It was observed from Luedeking and Piret model that the lipase production was mixed growth associated with maximum activity at 37°C and at pH 7. Statistical optimization using Response Surface Methodology was performed to understand the interaction of different parameters and the standardized conditions obtained were as follows: Peptone 10 g/L, yeast extract 7.5 g/L and olive oil 14 mL/L. The predicted data were validated and the model predicted was significant with a maximum specific activity of 1.1 µmole/min/mg proteins. The lipasespecific activity was enhanced by 10% and 23% after a single parameter and statistical optimization.

scholarly journals Alpha-tocopheryl succinate (α-TOS) influences cell vitality and enzyme activity in Ehrlich ascites carcinoma cells

2007 ◽  
Vol 15 (3-4) ◽  
pp. 65-68
Author(s):  
Karmen Stankov ◽  
Katica Bajin-Katic ◽  
Bojan Stanimirov ◽  
Dunja Karadzic ◽  
Zoran Kovacevic
Keyword(s):  
Enzyme Activity ◽  
Anticancer Agents ◽  
Specific Activity ◽  
Ehrlich Ascites Carcinoma ◽  
Carcinoma Cells ◽  
Malignant Cells ◽  
Ehrlich Ascites ◽  
Tocopheryl Succinate ◽  
Eac Cells

Background: One of the most important strategies in research and development of new anticancer agents is the tumor-specific induction of apoptosis. The effects of semisynthetic derivative of vitamin E, (?-TOS, D-?-tocopheryl succinate), appear to be largely restricted to malignant cells. Methods: We investigated the in vivo effects of intraperitoneally administered ?-TOS on vitality of Ehrlich ascites carcinoma cells (EAC) in mice, as well as the influence of ?-TOS on specific activity of enzymes involved in antioxidative mechanisms in EAC cells. Results: According to our results, the intraperitoneal application of ?-TOS induces the decrease of the EAC vitality, and the statistically significant alteration of the glutathione-dependent enzyme activity in EAC cells. Conclusion: We may conclude that ?-TOS is an important micronutrient, with significant impact on vitality and metabolism of malignant cells.

scholarly journals THE ENZYMATIC DEGRADATION OF HEMOGLOBIN TO BILE PIGMENTS BY MACROPHAGES

1971 ◽  
Vol 133 (6) ◽  
pp. 1264-1281 ◽  
Author(s):  
Neville R. Pimstone ◽  
Raimo Tenhunen ◽  
Paul T. Seitz ◽  
Harvey S. Marver ◽  
Rudi Schmid
Keyword(s):  
Enzyme Activity ◽  
Heme Oxygenase ◽  
Specific Activity ◽  
Indirect Evidence ◽  
Reticuloendothelial System ◽  
Bile Pigments ◽  
Absolute Requirement ◽  
Oxygenase Activity ◽  
Alternate Routes

Recent studies have identified and characterized the enzymatic mechanism by which hemoglobin-heme is converted to bilirubin. Under physiologic conditions the enzyme system, microsomal heme-oxygenase, is most active in the spleen followed by the liver and bone marrow, all of which are tissues that normally are involved in the sequestration and metabolism of red cells. Indirect evidence suggested that the reticuloendothelial system is important in this process. To test this hypothesis, conversion of heme to bilirubin was studied in macrophages obtained by chemical or immunological means from the peritoneal cavity or from the lungs of rodents. Homogenates of pure populations of these cells were devoid of heme-oxygenase activity, unless before harvesting the macrophages had been exposed to methemalbumin, microcrystalline hemin, or hemoglobin in vivo. In macrophages exposed to heme pigments, the specific activity of heme-oxygenase was far in excess of that in the spleen or liver. Enzyme activity was also present in the granulomatous tissue surrounding subcutaneous hematomas. The heme-oxygenase system in macrophages resembles that in the spleen and liver in that it is localized in the microsomal fraction, has an absolute requirement for molecular oxygen and NADPH, is inhibited by carbon monoxide, and has a similar Km. These findings indicate that cells of the reticuloendothelial system, presumably including the Kupffer cells of the liver and the macrophages of the spleen, possess the enzymatic machinery for converting hemoglobin-heme to bilirubin. The reaction is a mixed function oxidation, probably involving cytochrome P450 as the terminal oxidase. Enzyme activity in macrophages is capable of regulatory adaptation in response to substrate loads. In the standard assay system for the enzyme, disappearance of heme always was in excess of the amount of bilirubin formed, suggesting the simultaneous presence of alternate routes of heme degradation not involving bilirubin as an end product or intermediate.

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