scholarly journals HygY Is a Twitch Radical SAM Epimerase with Latent Dehydrogenase Activity Revealed upon Mutation of a Single Cysteine Residue

2021 ◽  
Author(s):  
Ronald A. Besandre ◽  
Zhang Chen ◽  
Ian Davis ◽  
Jiawei Zhang ◽  
Mark Walter Ruszczycky ◽  
...  
Keyword(s):  
Dehydrogenase Activity ◽  
Cysteine Residue ◽  
Radical Sam

Sulfhydril Groups and the Concerted Inhibition of NADP+-Linked Isocitrate Dehydrogenase

1972 ◽  
Vol 50 (10) ◽  
pp. 1109-1113 ◽  
Author(s):  
Clive Little ◽  
Peggy Holland
Keyword(s):  
Binding Site ◽  
Dehydrogenase Activity ◽  
Isocitrate Dehydrogenase ◽  
Lipid Peroxide ◽  
Cysteine Residue ◽  
Sulfhydryl Groups ◽  
Sulfhydryl Reagents ◽  
Carboxylase Activity ◽  
X Irradiation

Mixtures of glyoxalate and oxaloacetate have been shown to inhibit highly purified pig heart NADP+ -linked isocitrate dehydrogenase in a strongly concerted manner. The α-ketoglutarate reductive carboxylase activity of the enzyme was also inhibited, but to a lesser extent than the dehydrogenase activity. Modification of sulfhydryl groups in the enzyme by certain reagents led to a diminution of the inhibition, although the extent of this effect depended on the reagent used. N-Ethylmaleimide was most effective at diminishing the concerted inhibition, whereas oxidation of the sulfhydryl groups by X-irradiation or lipid peroxide had no effect. It was concluded that the effect of sulfhydryl reagents on the inhibition was probably due to the modification of one specific cysteine residue which is possibly adjacent to the binding site on the enzyme for glyoxalate.

Mutations which Introduce Free Cysteine Residues in the Gla-Domain of Vitamin K Dependent Proteins Result in the Formation of Complexes with α1-Microglobulin

1996 ◽  
Vol 75 (01) ◽  
pp. 070-075 ◽  
Author(s):  
E G C Wojcik ◽  
P Simioni ◽  
M v d Berg ◽  
A Girolami ◽  
R M Bertina
Keyword(s):  
Vitamin K ◽  
Protein C ◽  
Cysteine Residue ◽  
Factor Ix ◽  
Disulphide Bond ◽  
Clotting Factors ◽  
High Molecular Weight Complex ◽  
Low Concentrations ◽  
Gla Domain ◽  
Formation Of Complexes

SummaryWe have previously described a genetic factor IX variant (Cys18→Arg) for which we demonstrated that it had formed a heterodimer with armicroglobulin through formation of a disulphide bond with the remaining free cysteine residue of the disrupted disulphide bond in the Gla-domain of factor IX. Recently, we observed a similar high molecular weight complex for a genetic protein C variant (Arg-1→Cys). Both the factor IX and the protein C variants have a defect in the calcium induced conformation. In this study we show that the aminoterminus of this protein C variant is prolonged with one amino acid, cysteine. This protein C variant, as well as protein C variants with Arg9→Cys and Ser12→Cys mutations which also carry a free cysteine residue, are shown to be present in plasma as a complex with α1-microglobulin. A prothrombin variant with a Tyr44→Cys mutation, had not formed such a complex. Furthermore, complexes between normal vitamin K-dependent clotting factors and α1-microglobulin were shown to be present in plasma at low concentrations. The data suggest that the presence of an unpaired cysteine residue in the propeptide or the N-terminal half of the Gla-domain has strongly promoted the formation of a complex with α1-microglobulin in the variants.

THE INFLUENCE OF HAEMOGLOBIN-S AND G6PD DEFICIENCY ON THE ACTIVITY OF THE 17β-HYDROXYSTEROID DEHYDROGENASE OF INTACT HUMAN ERYTHROCYTES

1974 ◽  
Vol 75 (4) ◽  
pp. 793-800
Author(s):  
A. O. Sogbesan ◽  
O. A. Dada ◽  
B. Kwaku Adadevoh
Keyword(s):  
Enzyme Activity ◽  
Dehydrogenase Activity ◽  
Sex Steroids ◽  
G6pd Deficiency ◽  
Incubation Medium ◽  
Hydroxysteroid Dehydrogenase ◽  
G6pd Activity ◽  
Reverse Transformation ◽  
Oxidative Transformation ◽  
Haemoglobin S

ABSTRACT The 17β-hydroxysteroid dehydrogenase activity in intact erythrocytes of Nigerian patients, in particular with regard to haemoglobin genotypes and G6PD* activity was studied. The G6PD activity of the erythrocyte did not affect the oxidative transformation of testosterone to androstenedione and of oestradiol to oestrone. The reduction (reverse transformation) was inhibited in G6PD-deficient erythrocytes but this inhibition was offset by the addition of 0.025 m glucose to the incubation medium. The per cent oxidation transformation of testosterone was higher in Hb-AA than in Hb-SS erythrocytes. It is suggested that the differences may be a result of either lower enzyme activity in the Hb-SS erythrocytes or of differences in the uptake and possibly binding of sex steroids by intact Hb-SS and Hb-AA erythrocytes.

ACUTE ENZYME HISTOCHEMICAL CHANGES IN THE ZONA GLOMERULOSA OF THE RAT ADRENAL CORTEX

1968 ◽  
Vol 59 (3) ◽  
pp. 508-518
Author(s):  
J. D. Elema ◽  
M. J. Hardonk ◽  
Joh, Koudstaal ◽  
A. Arends
Keyword(s):  
Peritoneal Dialysis ◽  
Succinate Dehydrogenase ◽  
Dehydrogenase Activity ◽  
Adrenal Cortex ◽  
Isocitrate Dehydrogenase ◽  
Hydroxysteroid Dehydrogenase ◽  
Zona Glomerulosa ◽  
Acute Changes ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Histochemical Changes

ABSTRACT Acute changes in glucose-6-phosphate dehydrogenase and isocitrate dehydrogenase activity in the zona glomerulosa of the rat adrenal cortex were induced by peritoneal dialysis with 5 % glucose. Although less clear, the activity of 3β-ol-hydroxysteroid dehydrogenase also seemed to increase as well. No changes were seen in the activity of succinate dehydrogenase. Dialysis with 0.9 % NaCl had no effect on any of the enzymes investigated. The possible significance of these observations is discussed.

Pyruvate dehydrogenase activity in cardiac mitochondria from genetically diabetic mice

Diabetes ◽  
1985 ◽  
Vol 34 (11) ◽  
pp. 1075-1081 ◽  
Author(s):  
T. H. Kuo ◽  
F. Giacomelli ◽  
J. Wiener ◽  
K. Lapanowski-Netzel
Keyword(s):  
Dehydrogenase Activity ◽  
Pyruvate Dehydrogenase ◽  
Diabetic Mice ◽  
Cardiac Mitochondria ◽  
Genetically Diabetic Mice
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