Induction of tyrosinase by L-methionine in Streptomyces antibioticus

1988 ◽  
Vol 34 (12) ◽  
pp. 1297-1303 ◽  
Author(s):  
Edward Katz ◽  
Aline Betancourt
Keyword(s):  
Enzyme Activity ◽  
Actinomycin D ◽  
Enzyme Synthesis ◽  
Streptomyces Antibioticus ◽  
Activity Inhibition

Investigations were carried out to establish conditions favorable for the formation of tyrosinase, an inducible metalloenzyme synthesized by Streptomyces antibioticus. It was determined that the size of the inoculum and age of the culture as well as the temperature of incubation were important factors for enzyme synthesis. Induction of tyrosinase by S. antibioticus appears to be specific for L-methionine with maximal enzyme synthesis observed at 0.1 mM. Addition of CuSO4 and D-glucose at the time of induction also are important for increased enzyme activity. Inhibition of tyrosinase synthesis was observed with actinomycin D, rifampicin, and chloramphenicol suggesting that both transcriptional and translational events are required for tyrosinase induction.

scholarly journals TEMPORAL ORDER IN MAMMALIAN CELLS

1969 ◽  
Vol 43 (2) ◽  
pp. 207-219 ◽  
Author(s):  
Robert R. Klevecz
Keyword(s):  
Enzyme Activity ◽  
Mammalian Cells ◽  
Temporal Order ◽  
Actinomycin D ◽  
Chinese Hamster ◽  
Enzyme Synthesis ◽  
S Phase ◽  
Selection System ◽  
Enzyme Protein ◽  
Chinese Hamster Cells

Chinese hamster cells were synchronized by the Colcemid-selection system. In cells with a division cycle time of 11.5–12 hr, the activity of the enzyme lactate dehydrogenase (LDH) underwent marked oscillations with a 3.5-hr period. Precipitation of labeled LDH enzyme with specific antibody indicated that the enzyme activity changes were the result of intermittent enzyme synthesis and relatively constant degradation. Inhibition of normal DNA replication with 4 mM of thymidine, while reducing the amount of new enzyme synthesized, did not prevent oscillations from occurring. Similarly, actinomycin D (AcD) added at the time of synchronization allowed some new enzyme synthesis to proceed in an oscillatory manner. LDH synthesis went on at nearly normal rates when AcD was added in the middle of S phase. However, addition of cycloheximide to cultures at any time in the cycle caused an immediate drop in levels of activity and in enzyme protein. The half-life of LDH, calculated either from loss of enzyme activity or precipitable radioactivity in cycloheximide-treated cultures, was between 2 and 2.5 hr.

scholarly journals Phosphopyruvate carboxylase induction by l-tryptophan. Effects on synthesis and degradation of the enzyme

1973 ◽  
Vol 136 (2) ◽  
pp. 259-264 ◽  
Author(s):  
F. J. Ballard ◽  
M. F. Hopgood
Keyword(s):  
Enzyme Activity ◽  
Specific Antibody ◽  
Actinomycin D ◽  
Relative Rate ◽  
Enzyme Synthesis ◽  
Enzyme Protein ◽  
Carboxylase Activity ◽  
Twofold Increase ◽  
Synthesis And Degradation

1. The administration of l-tryptophan to fed rats produces a twofold increase in hepatic phosphopyruvate carboxylase activity that represents a comparable increase in enzyme protein. With specific antibody against the enzyme we have shown that the increase in phosphopyruvate carboxylase is partially mediated via an actinomycin D-sensitive increase in enzyme synthesis. 2. In starved animals tryptophan increases the enzyme activity without any change in the relative rate of phosphopyruvate carboxylase synthesis. In this condition degradation of the enzyme is retarded by tryptophan by a mechanism that is not prevented by cycloheximide.

scholarly journals Biphasic effect of acute ethanol administration on rat liver tyrosine-2-oxoglutarate aminotransferase activity

1980 ◽  
Vol 186 (3) ◽  
pp. 755-761 ◽  
Author(s):  
A A B Badawy ◽  
B M Snape ◽  
M Evans
Keyword(s):  
Enzyme Activity ◽  
Rat Liver ◽  
Actinomycin D ◽  
Tyrosine Aminotransferase ◽  
Ethanol Metabolism ◽  
Ethanol Administration ◽  
Aminotransferase Activity ◽  
Biphasic Effect ◽  
Initial Decrease ◽  
Acute Ethanol

1. Acute ethanol administration causes a biphasic change in rat liver tyrosine aminotransferase activity. 2. The initial decrease is significant with a 200 mg/kg dose of ethanol, is prevented by adrenoceptor-blocking agnets and by reserpine, but not by inhibitors of ethanol metabolism, and exhibits many of the characteristics of the inhibition caused by noradrenaline. 3. The subsequent enhancement of the enzyme activity by ethanol is not associated with stabilization of the enzyme, but is sensitive to actinomycin D and cycloheximide. 4. It is suggested that the initial decrease in aminotransferase activity is caused by the release of catecholamines, whereas the subsequent enhancement may be related to the release of glucocorticoids.

Electrochemical investigations of lipase enzyme activity inhibition by methyl parathion pesticide: Voltammetric studies

2013 ◽  
Vol 180 ◽  
pp. 26-30 ◽  
Author(s):  
K. Gangadhara Reddy ◽  
G. Madhavi ◽  
B.E. Kumara Swamy ◽  
Sathish Reddy ◽  
A.Vijaya Bhaskar Reddy ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Methyl Parathion ◽  
Activity Inhibition ◽  
Lipase Enzyme ◽  
Voltammetric Studies

scholarly journals Detection of phosphatase activity in aquatic and terrestrial cyanobacterial strains

2013 ◽  
pp. 31-42
Author(s):  
Olivera Babic ◽  
Jelica Simeunovic ◽  
Natasa Skrbic ◽  
Dajana Kovac ◽  
Zorica Svircev
Keyword(s):  
Enzyme Activity ◽  
Specific Property ◽  
Enzyme Synthesis ◽  
Ecological Group ◽  
Extreme Conditions ◽  
Survival Strategy ◽  
Acid Phosphatases ◽  
Nitrogen Fixing ◽  
Cyanobacterial Strain ◽  
Alkaline Phosphatases

Cyanobacteria, as highly adaptable microorganisms, are characterized by an ability to survive in different environmental conditions, in which a significant role belongs to their enzymes. Phosphatases are enzymes produced by algae in relatively large quantities in response to a low orthophosphate concentration and their activity is significantly correlated with their primary production. The activity of these enzymes was investigated in 11 cyanobacterial strains in order to determine enzyme synthesis depending on taxonomic and ecological group of cyanobacteria. The study was conducted with 4 terrestrial cyanobacterial strains, which belong to Nostoc and Anabaena genera, and 7 filamentous water cyanobacteria of Nostoc, Oscillatoria, Phormidium and Microcystis genera. The obtained results showed that the activity of acid and alkaline phosphatases strongly depended on cyanobacterial strain and the environment from which the strain originated. Higher activity of alkaline phosphatases, ranging from 3.64 to 85.14 ?molpNP/s/dm3, was recorded in terrestrial strains compared to the studied water strains (1.11-5.96 ?molpNP/s/dm3). The activity of acid phosphatases was higher in most tested water strains (1.67-6.28 ?molpNP/s/dm3) compared to the activity of alkaline phosphatases (1.11-5.96 ?molpNP/s/dm3). Comparing enzyme activity of nitrogen fixing and non-nitrogen fixing cyanobacteria, it was found that most nitrogen fixing strains had a higher activity of alkaline phosphatases. The data obtained in this work indicate that activity of phosphatases is a strain specific property. The results further suggest that synthesis and activity of phosphatases depended on eco-physiological characteristics of the examined cyanobacterial strains. This can be of great importance for the further study of enzymes and mechanisms of their activity as a part of cyanobacterial survival strategy in environments with extreme conditions.

Ornithine decarboxylase in rat small intestine: stimulation with food or insulin

1976 ◽  
Vol 231 (5) ◽  
pp. 1557-1561 ◽  
Author(s):  
DV Maudsley ◽  
J Leif ◽  
Y Kobayashi
Keyword(s):  
Enzyme Activity ◽  
Small Intestine ◽  
Ornithine Decarboxylase ◽  
Diamine Oxidase ◽  
Actinomycin D ◽  
Histidine Decarboxylase ◽  
Decarboxylase Activity ◽  
Adenosylmethionine Decarboxylase ◽  
Diamine Oxidase Activity ◽  
Similarities And Differences

Ornithine decarboxylase in the small intestine of starved rats was stimulated 3- to 10-fold by refeeding or administration of insulin. A peak is observed 3-5 h following treatment after which the enzyme activity rapidly declines. The rise in ornithine decarboxylase is reduced by actinomycin D or cycloheximide. The increase in enzyme activity occurs mainly in the duodenum and jejunum with less than a twofold change being observed in the ileum. A small (twofold) increase in S-adenosylmethionine decarboxylase activity in the small intestine was observed after food, but there was no change in diamine oxidase activity. Whereas pentagastrin and metiamide administration markedly stimulated histidine decarbosylase in the gastric mucosa, no consistent effect of these agents on ornithine decarboxylase in the small intestine was observed. The similarities and differences between histidine decarboxylase and ornithine decarboxylase are discussed.

Regulation of Chloramphenicol Synthesis in Streptomyces sp. 3022a. 3-Deoxy-D-arabino-heptulosonate 7-Phosphate Synthetase

1971 ◽  
Vol 49 (4) ◽  
pp. 448-455 ◽  
Author(s):  
D. A. Lowe ◽  
D. W. S. Westlake
Keyword(s):  
Enzyme Activity ◽  
Shikimic Acid ◽  
Aromatic Amino Acids ◽  
Product Inhibition ◽  
Enzyme Synthesis ◽  
Synthetase Activity ◽  
Shikimic Acid Pathway ◽  
Sugar Phosphates ◽  
Acid Pathway ◽  
Single Enzyme

The repression and end-product inhibition of 3-deoxy-D-arabino-heptulosonate 7-phosphate (DAHP) synthetase were studied in a chloramphenicol-producing Streptomycetes. Synthesis of DAHP synthetase was repressed by p-hydroxybenzoate, and enzyme activity was inhibited competitively by sugar phosphates, especially D-ribose 5-phosphate. The presence of chloramphenicol, aromatic amino acids, or shikimic acid pathway intermediates did not repress enzyme synthesis nor inhibit enzyme activity. Chloramphenicol production by growing cultures was not affected by the intermediates or end products of the shikimic acid pathway nor by the repression of DAHP synthetase. Purification of DAHP synthetase activity indicated the presence of a single enzyme protein with a molecular weight of 88 000.

Development of Isocitric Lyase Activity in Germinating Prickly Sida Seed

Weed Science ◽  
1976 ◽  
Vol 24 (3) ◽  
pp. 298-301 ◽  
Author(s):  
Bonnie J. Reger ◽  
E. Wayne Smith
Keyword(s):  
Enzyme Activity ◽  
Actinomycin D ◽  
Maximum Activity ◽  
Lyase Activity ◽  
Radicle Protrusion ◽  
Sida Spinosa ◽  
D 12 ◽  
Prickly Sida

Maximum activity of isocitric lyase (EC 4.1.3.1) was reached at 24 hr incubation of afterripened (nondormant) prickly sida (Sida spinosaL.) seed. Enzyme activity declined gradually with incubation times in excess of 24 hr. Actinomycin D (Act D) at 5 μg/ml had essentially no effect on 24-hr germination but inhibited development of isocitric lyase activity 83%. Cycloheximide (CH) at 10 μg/ml inhibited 24-hr germination of punctured seed only 7% but inhibited development of isocitric lyase activity 76%. Seed incubated in water 12 hr before being transferred to Act D at 5 μg/ml for an additional 12 hr did not escape sensitivity to the antibiotic. Isocitric lyase activity was inhibited when assayed at 24 hr total incubation. In the reverse experiment, seed incubated in Act D 12 hr before being transferred to water, isocitric lyase activity at 24 hr was not affected. Apparently prickly sida seed lacked a performed mRNA for isocitric lyase and transcription and translation of the mRNA occurred shortly after initiation of radicle protrusion (~8 hr).

1,25-Dihydroxyvitamin D3-inducible catabolism of vitamin D metabolites in mouse intestine

1990 ◽  
Vol 258 (4) ◽  
pp. G557-G563 ◽  
Author(s):  
M. Tomon ◽  
H. S. Tenenhouse ◽  
G. Jones
Keyword(s):  
Vitamin D ◽  
Enzyme Activity ◽  
Actinomycin D ◽  
Vitamin D Metabolites ◽  
Catabolic Pathway ◽  
Dihydroxyvitamin D3 ◽  
Oxidation Pathway ◽  
1,25 Dihydroxyvitamin D3 ◽  
Mouse Intestine ◽  
Alpha Amanitin

The 1,25-dihydroxyvitamin D3 [1,25(OH)2D3]-inducible C-24 oxidation pathway is a major catabolic pathway for vitamin D metabolites in target tissues. Using intestinal homogenates derived from 1,25(OH)2D3-treated mice, we examined the time course of induction, the intestinal localization and kinetics of induced enzyme activity, as well as the sensitivity of induction to transcriptional inhibitors actinomycin D and alpha-amanitin. 24-Hydroxylation of 500 nM 3H-labeled 25-hydroxyvitamin D3 [25(OH)D3] and 50 nM 3H-labeled 1,25(OH)2D3 by duodenal homogenates was detected 1 h after 1,25(OH)2D3 treatment; C-24 oxidation products of 25(OH)D3 and 1,25(OH)2D3 peaked at approximately 6 h and remained elevated for 17 h. Induced enzyme activity was localized to the mitochondrial fraction, was highest in duodenum, and was also detected in jejunum, ileum, and colon. The apparent Michaelis constant of the induced duodenal enzyme for 25(OH)D3 was 451 nM and for 1,25(OH)2D3 was 14 nM. Induction of intestinal catabolic activity was inhibited by prior treatment of 1,25(OH)2D3-injected mice with either actinomycin D or alpha-amanitin. The characteristics of the 1,25(OH)2D3-inducible C-24 oxidation pathway in the intestine resembled that of the kidney. However, the catabolic pathway was constitutively expressed only in the kidney. We conclude that 1,25(OH)2D3-inducible degradation of vitamin D metabolites occurs throughout the length of mouse intestine and can be prevented by transcriptional inhibitors, suggesting that mRNA synthesis is required for the induction process.

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