scholarly journals THE EFFECT OF HEAT, INHIBITORS, AND RIBOFLAVIN DEFICIENCY ON MONOAMINE OXIDASE

1965 ◽  
Vol 43 (8) ◽  
pp. 1305-1318 ◽  
Author(s):  
Moussa B. H. Youdim ◽  
T. L. Sourkes
Keyword(s):  
Monoamine Oxidase ◽  
Chelating Agents ◽  
Liver Mitochondria ◽  
Borate Buffer ◽  
Rat Liver Mitochondria ◽  
Mitochondrial Enzyme ◽  
Riboflavin Deficiency ◽  
Different Types ◽  
The Stability ◽  
Riboflavin Deficient

The stability of monoamine oxidase of rat liver mitochondria to heating has been studied, using kynuramine as substrate in a spectrophotometric assay. After suspensions of mitochondria were heated for 50 minutes at 50°, about 30% of the enzymatic activity is lost; at 53° for the same time, 50% is lost. At 60° most of the activity is lost in the first 10 minutes. Activity as a function of pH was studied; resulting curves had a shoulder around pH 6.5 and a peak at pH 7.4 in phosphate buffer (or at 8.1 in borate buffer). The corresponding curves for heated suspensions of mitochondria (50°, 30 minutes) showed a relatively greater decrease in activity at pH 7.0 than at pH 6.5. This resulted in the disappearance of the shoulder and the appearance of a new peak at pH 6.5. Tranylcypromine and iproniazid inhibited the mitochondrial enzyme more strongly at pH 8.1 (borate buffer) than at the lower pH's, but pargyline inhibited more at pH 6.5. Chelating agents such as 8-hydroxyquinoline and thenoyltrifluoroacetone inhibited the enzyme more strongly at the lower pH's. Extracts of livers of riboflavin-deficient rats showed less activity than those from vitamin-supplemented animals. Substrates and certain inhibitors of monoamine oxidase protected the enzyme from inactivation during heating, but amines that are not substrates provided no such protection. Unsuccessful attempts were made to identify different types of monoamine oxidase activity in the mitochondria fractionated on sucrose density gradients.

scholarly journals Effects of riboflavin deficiency and clofibrate treatment on the five acyl-CoA dehydrogenases in rat liver mitochondria

1988 ◽  
Vol 254 (2) ◽  
pp. 477-481 ◽  
Author(s):  
K Veitch ◽  
J P Draye ◽  
F Van Hoof ◽  
H S A Sherratt
Keyword(s):  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Straight Chain ◽  
Riboflavin Deficiency ◽  
Deficient Diet ◽  
Mitochondrial Fractions ◽  
Chain Acyl ◽  
Branched Chain ◽  
Acyl Coa Dehydrogenases ◽  
Riboflavin Deficient

Rats were maintained on a riboflavin-deficient diet or on a diet containing clofibrate (0.5%, w/w). The activities of the mitochondrial FAD-dependent straight-chain acyl-CoA dehydrogenases (butyryl-CoA, octanoyl-CoA and palmitoyl-CoA) and the branched-chain acyl-CoA dehydrogenases (isovaleryl-CoA and isobutyryl-CoA) involved in the degradation of branched-chain acyl-CoA esters derived from branched-chain amino acids were assayed in liver mitochondrial extracts prepared in the absence and presence of exogenous FAD. These activities were low in livers from riboflavin-deficient rats (11, 28, 16, 6 and less than 2% of controls respectively) when prepared in the absence of exogenous FAD, and were not restored to control values when prepared in 25 microM-FAD (29, 47, 28, 7 and 17%). Clofibrate feeding increased the activities of butyryl-CoA, octanoyl-CoA and palmitoyl-CoA dehydrogenases (by 48, 116 and 98% of controls respectively), but not, by contrast, the activities of isovaleryl-CoA and isobutyryl-CoA dehydrogenases (62 and 102% of controls respectively). The mitochondrial fractions from riboflavin-deficient and from clofibrate-fed rats oxidized palmitoylcarnitine in State 3 at rates of 32 and 163% respectively of those from control rats.

Comparative studies of CDP-diacylglycerol synthase in rat liver mitochondria and microsomes

1993 ◽  
Vol 71 (3-4) ◽  
pp. 183-189 ◽  
Author(s):  
Amy Y. P. Mok ◽  
Gordon E. McDougall ◽  
William C. McMurray
Keyword(s):  
Phosphatidic Acid ◽  
Rat Liver ◽  
Mitochondrial Fraction ◽  
Liver Mitochondria ◽  
Subcellular Fractions ◽  
Rat Liver Mitochondria ◽  
Mitochondrial Enzyme ◽  
Egg Lecithin ◽  
Microsomal Membranes ◽  
Concentration Curves

CDP-diacylglycerol for polyglycerophosphatide biogenesis can be synthesized within rat liver mitochondria. Contamination by microsomal membranes cannot account for the CDP-diacylglycerol synthesis found in the mitochondria. Phosphatidic acid from egg lecithin was the best substrate for the synthesis of CDP-diacylglycerol in both subcellular fractions. Concentration curves for CTP and Mg2+ differed for the two subcellular fractions. Microsomal CDP-diacylglycerol synthase was specifically stimulated by the nucleotide GTP; this stimulatory effect by GTP was not observed in the mitochondrial fraction. By comparison, the microsomal enzyme was more sensitive towards sulfhydryl inhibitors than the mitochondrial enzyme. The enzymes could be solubilized from the membrane fractions using 3-[(cholamidopropyl)dimethylammonio]-1-propanesulfonate, and the detergent-soluble activity could be partially restored by addition of phospholipids. Based on the differences in properties, it was concluded that there are two distinct enzyme localizations for CDP-diacylglycerol synthesis in mitochondria and microsomes from rat liver.Key words: CDP-diacylglycerol, synthase, phosphatidic acid, mitochondria, microsomes, solubilization.

Action of khimcoccid on monoamine oxidase of rat liver mitochondria

1982 ◽  
Vol 16 (2) ◽  
pp. 77-82
Author(s):  
V. I. Zaionts ◽  
L. A. Korovitskaya ◽  
E. B. Nikol'skaya ◽  
O. V. Yagodina
Keyword(s):  
Monoamine Oxidase ◽  
Rat Liver ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria

scholarly journals Glutathione reductase deficiency in Saudi Arabia

1999 ◽  
Vol 5 (6) ◽  
pp. 1208-1212
Author(s):  
A. S. Warsy ◽  
M. A. El Hazmi
Keyword(s):  
Glutathione Reductase ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Normal Functioning ◽  
Riboflavin Deficiency ◽  
Males And Females ◽  
Presence And Absence ◽  
Glutathione Reductase Deficiency ◽  
The Stability ◽  
Riboflavin Deficient ◽  
Reduced Nicotinamide Adenine Dinucleotide

Glutathione reductase [GR]is a ubiquitous enzyme required for the conversion of oxidized glutathione [GSSG] to reduced glutathione [GSH] concomitantly oxidizing reduced nicotinamide adenine dinucleotide phosphate [NADPH]in a reaction essential for the stability and integrity of red cells. Mutations in the GR gene and nutritional deficiency of riboflavin, a co-factor required for the normal functioning of GR, can cause GR deficiency. We conducted a study on 1691 Saudi individuals to determine the overall frequency of GR deficiency and to identify whether the deficiency results from genetic or acquired causes or both. The activity of GR was measured in freshly prepared red cell haemolysate in the presence and absence of flavin adenine dinucleotide [FAD]and the activity coefficient [AC] was determined. Samples with low GR activity [>2.0 IU/g haemoglobin] both in the presence and absence of FAD and an AC between 0.9 and 1.2 were considered GR-deficient. Samples with AC >/= 1.3 were considered riboflavin-deficient. The overall frequency of partial GR deficiency was 24.5% and 20.3% in males and females respectively. In addition, 17.8% of males and 22.4% of females suffered from GR deficiency due to riboflavin deficiency. This could be easily corrected by dietary supplementation with riboflavin. No cases of severe GR deficiency were identified

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