Sinapine Esterase I. Characterization of Sinapine Esterase from Cotyledons of Raphanus sativus

1979 ◽  
Vol 34 (9-10) ◽  
pp. 715-720 ◽  
Author(s):  
Gerhild Nurmann ◽  
Dieter Strack
Keyword(s):  
Enzyme Activity ◽  
Esterase Activity ◽  
Raphanus Sativus ◽  
Sinapic Acid ◽  
Inhibitory Effect ◽  
Ph Optimum ◽  
Diisopropyl Fluorophosphate ◽  
E 600 ◽  
Red Radish

Abstract From cotyledons of Raphanus sativus (red radish) an esterase activity which catalyzes the hy­drolysis of sinapine into sinapic acid and choline has been isolated. The enzyme, which has a near absolute specificity, is not analogous with any esterase described in the literature. The reaction has a pH optimum of 8.5 and the apparent Km is 1.95 × 10-5 m. The enzyme is relatively insensi­tive to both physostigmine (eserine) {Ki = 1.73 × 10-4 m) and neostigmine (Ki = 2 .1 3 × 10-4 ᴍ). Diisopropyl fluorophosphate (DFP) showed no inhibition and diethyl p-nitrophenylphosphate (E 600) only a slight inhibitory effect at 10-5 ᴍ, respectively. Choline (10-2 ᴍ) was inhibitory but acetylcholine (10-2 ᴍ) stimulated the enzyme activity.

Enzymatic Synthesis of 1-Sinapoylglucose from Free Sinapic Acid and UDP-Glucose by a Cell-Free System from Raphanus sativus Seedlings

1980 ◽  
Vol 35 (3-4) ◽  
pp. 204-208 ◽  
Author(s):  
Dieter Strack
Keyword(s):  
Phenolic Acids ◽  
Enzymatic Synthesis ◽  
Raphanus Sativus ◽  
High Performance ◽  
Sinapic Acid ◽  
Carboxyl Group ◽  
Ph Optimum ◽  
Free System ◽  
Sh Group ◽  
A Cell

Abstract Protein extracts from seedlings of Raphanus sativus catalyze the transfer of the glucosyl moiety of UDP-glucose to the carboxyl group of phenolic acids. Enzymatic activity was determined spectrophotometrically by measuring the increase in absorbance at 360 nm and/or by the aid of high performance liquid chromatography (HPLC). From 12 phenolic acids tested as acceptors, sinapic acid was by far the best substrate. The glucosyltransfer to sinapic acid has a pH optimum near 7 and requires as SH group for activity, p-Chloromercuribenzoate (PCMB) inhibits activity, which can be restored by the addition of dithiothreitol (DTT). The formation of 1-sinapoylglucose was found to be a reversible reaction, since the addition of UDP results in a breakdown of the ester.

scholarly journals Biochemical characterization of Burkina red radish (Raphanus sativus) peroxidase

2018 ◽  
Vol 125 (1) ◽  
pp. 12518
Author(s):  
Mamounata Diao ◽  
Crépin I. Dibala ◽  
Brice N’cho Ayékoué ◽  
Mamoudou H. Dicko
Keyword(s):  
Raphanus Sativus ◽  
Biochemical Characterization ◽  
Red Radish

Characterization of CDPdiacylglycerol hydrolase in mitochondrial and microsomal fractions from rat lung

1988 ◽  
Vol 66 (5) ◽  
pp. 425-435 ◽  
Author(s):  
Amy Mok ◽  
Tanya Wong ◽  
Octavio Filgueiras ◽  
Paul G. Casola ◽  
Don W. Nicholson ◽  
...  
Keyword(s):  
Divalent Cations ◽  
Mitochondrial Fraction ◽  
Liver Mitochondria ◽  
Inhibitory Effect ◽  
Mitochondrial Activity ◽  
Rat Lung ◽  
Ph Optimum ◽  
Low Concentrations ◽  
Mercuric Ions

CDPdiacylglycerol pyrophosphatase (E. C. 3.6.1.26) activity has been examined in rat lung mitochondrial and microsomal fractions. While the mitochondrial hydrolase exhibited a broad pH optimum from pH 6–8, the microsomal activity decreased rapidly above pH 6.5. Apparent Km values of 36.2 and 23.6 μM and Vmax values of 311 and 197 pmol∙min−1∙mg protein−1 were observed for the mitochondrial and microsomal preparations, respectively. Addition of parachloromercuriphenylsulphonic acid led to a marked inhibition of the microsomal fraction but slightly stimulated the mitochondrial activity at low concentrations. Mercuric ions were inhibitory with both fractions. Although biosynthetic reactions utilizing CDPdiacylglycerol require divalent cations, addition of Mg2+, Mn2+, Ca2+, Zn2+, Co2+, and Cu2+ all inhibited the catabolic CDPdiacylglycerol hydrolase activity in both fractions. EDTA and EGTA also produced an inhibitory effect, especially with the mitochondrial fraction. Although addition of either adenine or cytidine nucleotides led to a decrease in activity with both fractions, the marked susceptibility to AMP previously reported for this enzyme in Escherichia coli membranes, guinea pig brain lysosomes, and pig liver mitochondria was not observed. These results indicate that rat lung mitochondria and microsomes contain specific CDPdiacylglycerol hydrolase activities, which could influence the rate of formation of phosphatidylinositol and phosphatidylglycerol for pulmonary surfactant.

UDP-Glucose: Flavonol 7-O-glucosyltransferase Activity in Flower Extracts of Chrysanthemum segetum

1997 ◽  
Vol 52 (3-4) ◽  
pp. 153-158 ◽  
Author(s):  
K. Stich ◽  
H. Halbwirth ◽  
F. Wurst ◽  
G. Forkmann
Keyword(s):  
Enzyme Activity ◽  
Specific Activity ◽  
Temperature Stability ◽  
Inhibitory Effect ◽  
Hydroxyl Group ◽  
Ph Optimum ◽  
Yellow Colour ◽  
Commercial Strain ◽  
Strong Inhibitory Effect ◽  
Chrysanthemum Segetum

Abstract The yellow colour of Chrysanthemum segetum petals is due to the presence of the 7-O-glucosides of quercetin and particularly gossypetin (8-hydroxyquercetin). In petal extracts of C. segetum an enzyme was demonstrated which catalyzes the transfer of the glucosyl moiety of uridine 5'-diphosphoglucose (UDPG) to the 7-hydroxyl group of flavonols with gossypetin and quercetin as the best substrates. Besides flavonols flavanones and flavones were found to be glucosylated in the 7-position. The pH-optimum of the reaction highly depended on the substrate used. With quercetin as substrate, maximal enzyme activity occurred at a pH of 8.25 and a temperature of 25 °C, but 7-O-glucosylation also proceeded at low temperatures. Studies on temperature stability revealed, that there was no influence on the glucosylation reaction up to 40 °C. Higher temperatures led to a loss of enzyme activity. Using gossypetin as a substrate a similar course of temperature stability was observed. Addition of Mg2+, Ca2+ and KCN slightly stimulated 7-O-glucosylation, whereas Co2+, Cu2+, Fe2+, Hg2+, p-hydroxymercuribenzoate and N-ethylmaleimide showed a strong inhibitory effect. Additional enzymatic studies were performed with the commercial strain " Stern des Orients" where gossypetin 7-O-glucoside is restricted to the inner parts of the petals. For enzyme extracts from both parts of the petals gossypetin was found to be the most attractive substrate. In comparison to quercetin (133.4 μkat / kg protein) an about three times higher specific activity of the 7-O-glucosyltransferase(s) was determined with gossypetin (382.1 μkat/ kg protein) as substrate, indicating that hydroxylation of quercetin in 8-position to gossypetin precedes 7-O-glucosylation.

Purification and Characterization of Three Extracellular Proteinases Produced by Pseudomonas fluorescens INIA 745, an Isolate from Ewe's Milk

1999 ◽  
Vol 62 (5) ◽  
pp. 543-546 ◽  
Author(s):  
J. FERNÁNDEZ ◽  
A. F. MOHEDANO ◽  
P. GAYA ◽  
M. MEDINA ◽  
M. NUÑEZ
Keyword(s):  
Pseudomonas Fluorescens ◽  
Culture Medium ◽  
Inhibitory Effect ◽  
Divalent Metal ◽  
Divalent Metal Ions ◽  
Purification And Characterization ◽  
Ph Optimum ◽  
Extracellular Proteinases ◽  
Ewe's Milk

Three proteinases were isolated from culture medium of Pseudomonas fluorescens INIA 745 and purified to homogeneity by a combination of Phenyl-Sepharose, DEAE-Sepharose, and Sephadex G-100 chromatography. Optimal temperature for enzymatic activity was 45°C for all three proteinases. The pH optimum of proteinases I and II was found to be 7.0, while that of proteinase III was 8.0. Divalent metal ions like Cu2+, Co2+, Zn2+, Fe2+, and Hg2+ were inhibitory to proteinase activity while Ca2+, Mg2+, and Mn2+ had little or no inhibitory effect. The three enzymes were strongly inhibited by EDTA and 1,10-phenantroline and partially by cysteine. The three enzymes are metalloproteinases since they were inhibited by chelators and reactivated by Co2+, Mn2+, Cu2+, and Zn2+. The Km values of proteinases I, II, and III for casein were calculated to be 3.2, 2.6, and 5.2 mg/ml, respectively. Proteinases II and III rapidly degraded β-casein, with preference to αs1-casein, whereas proteinase I hydrolyzed both casein fractions at a slow rate.

Separation, Partial Purification and Characterization of a Fatty Acid Hydroperoxide Cleaving Enzyme from Apple and Tomato Fruits

1982 ◽  
Vol 37 (3-4) ◽  
pp. 165-173 ◽  
Author(s):  
P. Schreier ◽  
G. Lorenz
Keyword(s):  
Fatty Acid ◽  
Inhibitory Effect ◽  
Fatty Acid Hydroperoxide ◽  
Partial Purification ◽  
Purification And Characterization ◽  
Ph Optimum ◽  
Isoelectric Points ◽  
Acid Hydroperoxide ◽  
Membrane Bound

Abstract A membrane-bound enzyme catalysing the cleavage of 13-hydroperoxy-(Z)-9,(E)-11-oc-tadecadienoic acid (13-LHPO) and 13-hydroperoxy-(Z)-9,(E)-11,(Z)-15-octadecadienoic acid (13-LnHPO) to C6-aldehydes was isolated and partially purified from apples and tomatoes. Attempts to employ Ultrogel AcA 34 and AcA 22 in a gel chromatographic purification step were partially frustrated by reaggregation phenomena. However, by using Sepharose CL-4 B an enzyme fraction (MW 200 000 Da) with lipoxygenase and fatty acid hydroperoxide cleaving activity could be separated from a high molecular-weight active eluate. By applying preparative isoelec­ tric focussing to the tomato protein we succeeded in separating the fatty acid cleaving activity from the lipoxygenase, because o f their different isoelectric points of pH 5.8 -6 .1 and pH 5.0, respectively, An 8.4-fold purification of the fatty acid cleaving activity was achieved. A pH-optimum of 5.5 and a Km-value of 2.6 × 10-5 м/1 for the 13-hydroperoxide of linoleic acid were measured. p-Chloromercuribenzoic acid (1 mм) showed significant inhibitory effect on the fatty acid hydroperoxide cleaving enzyme, but no evidence o f inhibition was found with 1 mм H2O2, KCN, DABCO and EDTA or superoxide dismutase (270 U). The maximum amount of fatty acid hydroperoxide decomposition (C6-aldehyde formation) was determined to be 59%.

scholarly journals CHARACTERIZATION OF CRUDE EXTRACT POLYPHENOLOXIDASE ENZYME FROM BLACK TIGER SHRIMP (Penaeus monodon)

2013 ◽  
Vol 5 (2) ◽  
Author(s):  
Made Suhandana ◽  
Tati Nurhayati ◽  
Laksmi Ambarsari
Keyword(s):  
Enzyme Activity ◽  
Metal Ion ◽  
Penaeus Monodon ◽  
Extraction Condition ◽  
Ph Optimum ◽  
Km Value ◽  
Shrimp Industry ◽  
Optimum Extraction ◽  
Inhibited Enzyme

<p>Shrimp is a  very important export  commodity with  high market value world wide. However, it is still facing problem related to the waste and deterioration quality as main issues for the shrimp industry. In this experiment, polyphenoloxidase from the carapace of Penaeus monodon was extracted and characterized. The research was carried out to obtain the optimum extraction condition and to evaluate the properties of enzyme i.e., pH, optimum temperature for activating enzyme, kinetic enzyme, and chelating on metal ion. The best method for PPO enzyme extraction used buffer with 1:3  proportion.  The optimum activity of enzyme was at pH 7 and temperature of 35°C. The kinematic enzyme (Km) value and the maximum substrate concentration were 5.42 mM and 7.5 mM, respectively.  Na<sup>+</sup>, Ca<sup>2+</sup>, Zn<sup>2+</sup>, and EDTA with concentration 5 and 10 mM inhibited enzyme activity.  Cu<sup>2+</sup>at concentration of 10 mM and Mn<sup>2+</sup> at concentration 5 mM also inhibited enzyme activity</p> <p>Keywords: carapace, characterization, polyphenoloxidase, shrimp</p>

scholarly journals Characterization of Activity of a Potential Food-Grade Leucine Aminopeptidase from Kiwifruit

2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
A. A. A. Premarathne ◽  
David W. M. Leung
Keyword(s):  
Enzyme Activity ◽  
Leucine Aminopeptidase ◽  
Deae Cellulose ◽  
Inhibitory Effect ◽  
Food Grade ◽  
The Core ◽  
Alkaline Conditions ◽  
Potential Food ◽  
Cellulose Column

Aminopeptidase (AP) activity in ripe but firm fruit of Actinidia deliciosa was characterized using L-leucine-p-nitroanilide as a substrate. The enzyme activity was the highest under alkaline conditions and was thermolabile. EDTA, 1,10-phenanthroline, iodoacetamide, and had inhibitory effect while a low concentration of dithiothreitol (DTT) had stimulatory effect on kiwifruit AP activity. However, DTT was not essential for the enzyme activity. The results obtained indicated that the kiwifruit AP was a thiol-dependent metalloprotease. Its activity was the highest in the seeds, followed by the core and pericarp tissues of the fruit. The elution profile of the AP activity from a DEAE-cellulose column suggested that there were at least two AP isozymes in kiwifruit: one unadsorbed and one adsorbed fractions. It is concluded that useful food-grade aminopeptidases from kiwifruit could be revealed using more specific substrates.

scholarly journals CHARACTERIZATION OF CRUDE EXTRACT POLYPHENOLOXIDASE ENZYME FROM BLACK TIGER SHRIMP (Penaeus monodon)

2013 ◽  
Vol 5 (2) ◽  
Author(s):  
Made Suhandana ◽  
Tati Nurhayati ◽  
Laksmi Ambarsari
Keyword(s):  
Enzyme Activity ◽  
Metal Ion ◽  
Penaeus Monodon ◽  
Extraction Condition ◽  
Ph Optimum ◽  
Km Value ◽  
Shrimp Industry ◽  
Optimum Extraction ◽  
Inhibited Enzyme

Shrimp is a  very important export  commodity with  high market value world wide. However, it is still facing problem related to the waste and deterioration quality as main issues for the shrimp industry. In this experiment, polyphenoloxidase from the carapace of Penaeus monodon was extracted and characterized. The research was carried out to obtain the optimum extraction condition and to evaluate the properties of enzyme i.e., pH, optimum temperature for activating enzyme, kinetic enzyme, and chelating on metal ion. The best method for PPO enzyme extraction used buffer with 1:3  proportion.  The optimum activity of enzyme was at pH 7 and temperature of 35°C. The kinematic enzyme (Km) value and the maximum substrate concentration were 5.42 mM and 7.5 mM, respectively.  Na+, Ca2+, Zn2+, and EDTA with concentration 5 and 10 mM inhibited enzyme activity.  Cu2+at concentration of 10 mM and Mn2+ at concentration 5 mM also inhibited enzyme activity Keywords: carapace, characterization, polyphenoloxidase, shrimp

scholarly journals Characterization of purified Polyphenol oxidase (PPO) from (Lactuca serriola L.) Prickly lettuce

2011 ◽  
Vol 5 (1) ◽  
pp. 40-50
Author(s):  
Mohammed. A. Al-Soufi
Keyword(s):  
Enzyme Activity ◽  
Potassium Cyanide ◽  
Inhibitory Effect ◽  
Lactuca Serriola ◽  
Primary Activity ◽  
Characterization Study ◽  
Optimum Ph ◽  
Prickly Lettuce ◽  
High Inhibition

In this study, purified PPO from Prickly lettuce were obratind from a previous characterization study. The results showed that the optimum pH were 6.5 and the pH stability profile showed that the enzyme were more stable at pH values 5.5-8, the optimum temperature for enzyme activity were 35ºC and the enzyme were stable at 35ºC for 10 min. the activation energy for conversion of substrate to product was 39.7194 Kj/mol, the purified enzyme lost its activity after 5 days of storage at 25ºC, while it lost (73 , 16)% of primary activity after 21 days of storage at 4 and -18ºC respectively, the purified enzyme contains 7.2% carbohydrates. It was noticed that all treated of enzyme with L-Cystein, Sodium metabisulphate and Dithiothretol at 1 and 10 mM revealed high inhibition for the enzyme activity, followed by citric acid, L-Ascorbic acid, EDTA and Potassium cyanide, while both Thiourea and Sodium benzoate showed less inhibitory effect. The Km and Vmax were (4.762 , 0.0588) mM/min respectively, while the coefficient Vmax/Km were 0.01235 min-1 for the purified enzyme when used Catechol as a substrate.

Sign in / Sign up

Export Citation Format

Share Document