Inhibition of wheat leaves nitrate reductase activity by Cibacron Blue

Albassam, Badr A.

doi:10.1080/15216549800204532

Cited by 3 publications

(2 citation statements)

References 2 publications

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“…The K i values for each SGST 26.5 inhibitor were determined by replotting the slopes obtained from the double reciprocal plots as a function of inhibitor concentration (Albassam 1998).…”

Section: Oligomeric Structurementioning

confidence: 99%

Purification, characterization and kinetic properties of the Taenia solium glutathione S -transferase isoform 26.5�kDa

Plancarte

Rendón

Landa

2004

Parasitology Research

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Glutathione S-transferases are major phase II detoxification enzymes. Taenia solium, a parasite of humans and pigs, is exposed to toxic products. The aim of this work was to purify and characterize a T. solium glutathione S-transferase isoform of 26.5 kDa (SGST26.5) in order to obtain its kinetic parameters. Homogeneous SGST26.5 was obtained by a simple purification procedure. SGST26.5 showed a p I of 7.07, and a native Mr of 60 kDa with 26.5 kDa subunits. The optimum activity for SGST26.5 was found at pH 6.5-7.0 in the range 10-42 degrees C. SGST26.5 had a specific enzyme activity of 78, 7.1, 6.6, and 0.7 microM min(-1) mg(-1) with CDNB, 1,2-dichloro-4-nitrobenzene, 2,4-hexadienal and trans-2-nonenal as substrates, respectively. It also had a kcat/ K(mCDNB)=2.15 x 10(3) M(-1 )s(-1), kcat/ KmGSH)=4.5 x 10(3) M(-1 )s(-1) and Vmax for GSH and CDNB=74 and 77 microM min(-1) mg(-1), respectively. SGST26.5 was inhibited in a noncompetitive form by cibacron blue, bromosulfophthalein and triphenyltin chloride. Inhibition studies as a function of inhibitor concentration show that the enzyme is a homodimer. Bireactant system analysis show that it follows an ordered sequential mechanism.

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“…The K i values for each SGST 26.5 inhibitor were determined by replotting the slopes obtained from the double reciprocal plots as a function of inhibitor concentration (Albassam 1998).…”

Section: Oligomeric Structurementioning

confidence: 99%

Purification, characterization and kinetic properties of the Taenia solium glutathione S -transferase isoform 26.5�kDa

Plancarte

Rendón

Landa

2004

Parasitology Research

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“…The results were registered spectrophotometrically at 340 nm. The Kis values for sodium arsenate cMDHTs inhibition, in both directions, were determined by replotting the slopes obtained from the double reciprocal plots (Lineweaver and Burk 1934) as a function of the inhibitor concentrations (Albassam 1998). …”

Section: Effect Of Temperaturementioning

confidence: 99%

Purification, properties, and kinetic studies of cytoplasmic malate dehydrogenase from Taenia solium cysticerci

2009

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Malate dehydrogenase (L: -malate: NAD oxidoreductase, EC 1.1.1.37) from the cytoplasm of Taenia solium cysticerci (cMDHTs) was purified 48-fold through a four-step procedure involving salt fractionation, ionic exchange, and dye affinity chromatography. cMDHTs had a native M (r) of 64,000, while the corresponding value per subunit, obtained under denaturing conditions, was 32,000. The enzyme is partially positive, with an isoelectric point of 8.7, and had a specific activity of 2,615 U mg(-1) in the reduction of oxaloacetate. The second to the 21st amino acids from cMDHTs N-terminal group were P G P L R V L I T G A A G Q I A Y N L S. This sequence is 100% identical to that of Echinococcus granulosus. Basic kinetic parameters were determined for this enzyme. The optimum pH for enzyme reaction was at 7.6 for oxaloacetate reduction and at 9.6 for malate oxidation. K (m) values for oxaloacetate, malate, NAD, and NADH were 2.4, 215, 50, and 48 microM, respectively. V (max) values for the substrates and cosubstrates as described above were 1,490, 87.8, 104, and 1,714 micromol min(-1) mg(-1). Several NAD analogs, structurally altered in either the pyridine or purine moiety, were observed to function as coenzymes in the reaction catalyzed by the purified malate dehydrogenase. cMDHTs activity was uncompetitive inhibited by arsenate for both the forward (Ki = 8.2 mM) and reverse (Ki = 77 mM) reactions. The mechanism of the cMDHTs reactivity was investigated kinetically by the product inhibition approach. The results of this study are qualitatively consistent with an Ordered Bi Bi reaction mechanism, in which only the coenzymes can react with the free enzyme.

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Inhibition of Wheat Leaf Nitrate Reductase Activity by Phenolic Compounds

Albassam

2000

Bioscience, Biotechnology, and Biochemistry

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Inhibition of wheat leaves nitrate reductase activity by Cibacron Blue

Cited by 3 publications

References 2 publications

Purification, characterization and kinetic properties of the Taenia solium glutathione S -transferase isoform 26.5�kDa

Purification, characterization and kinetic properties of the Taenia solium glutathione S -transferase isoform 26.5�kDa

Purification, properties, and kinetic studies of cytoplasmic malate dehydrogenase from Taenia solium cysticerci

Inhibition of Wheat Leaf Nitrate Reductase Activity by Phenolic Compounds

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