ABSTRACT
The development of experimental alloxan diabetes in rats was accompanied by the increase the activity of liver NADâº- and NADPâº-dependent malic enzymes (ME; NADâº-ME, EC 1.1.1.39 and NADPâº-ME, 1.1.1.40) associated with an increase in the rate of transcription of genes encoding these enzymes. Oral administration of aqueous extracts of Jerusalem artichoke and olive to diabetic rats caused a noticeable decrease in blood glucose, a decrease in the rate of transcription of the studied genes; and a decrease in ME activity towards normal values. Thus, extracts of Jerusalem artichoke and olive can be used as additives to the standard therapy of diabetes mellitus.
Subject(s)
Diabetes Mellitus, Experimental , Helianthus , Rats , Animals , NAD , NADP , Diabetes Mellitus, Experimental/drug therapy , Liver , Malate Dehydrogenase/geneticsABSTRACT
A significant decrease in the activity of lactate dehydrogenase (LDH, EC 1.1.1.27) in liver cells of rats with alloxan diabetes was found due to a decrease in the expression of the corresponding genes. The decrease in the activity of the enzyme under study in experimental type I diabetes was associated with inactivation of the cytoplasmic isoform of LDH. It was found that the level of ldha and ldhb gene transcripts in the liver of healthy rats was higher than in animals with alloxan diabetes. The ldha gene expression demonstrated almost 9-fold decrease, while a decrease in the ldhb gene expression was less pronounced (just 1.25-fold). Probably, the decrease in the rate of functioning of the enzyme under study is associated with a decrease in the intensity of glucose uptake by cells, which leads to inhibition of glycolysis and intensification of all stages of gluconeogenesis, particularly, reversed glycolysis reactions. Thus, the data obtained by us indicate an important role of LDH in the adaptive response of cellular metabolism in the development of type I diabetes mellitus.
Subject(s)
Diabetes Mellitus, Experimental , Animals , Isoenzymes/genetics , Isoenzymes/metabolism , L-Lactate Dehydrogenase/genetics , L-Lactate Dehydrogenase/metabolism , Liver/metabolism , RatsABSTRACT
An increase in the activity and the appearance of a new isoform of NAD-dependent malate dehydrogenase (MDH; EC 1.1.1.37) has been detected in the liver of rats with alloxan diabetes was revealed. This confirms the possibility of MDH involvement in the adaptive reaction of the body under oxidative tress caused by biochemical changes in diabetic animals. The increase in the hepatic MDH activity in rats with experimental type I diabetes mellitus (T1DM) is associated with the formation of an additional MDH isoform in peroxisomes. Data on the expression of the MDH encoding genes mdh1 and mdh2 confirm that in T1DM the increase in MDH activity occurs at the level of transcription of MDH encoding genes. The use of the extract of Helianthus tuberosus led to a marked decrease in the blood glucose concentration of rats with alloxan diabetes, abolished by the change in transcriptional activity of the studied genes and blocked the formation of new MDH isoforms in rats with experimental alloxan diabetes. This suggest that extract of H. tuberosus may be of considerable interest from the point of view of pharmacological correction of metabolic changes during the development of pathologies of this kind.
Subject(s)
Diabetes Mellitus, Experimental , Helianthus , Alloxan , Animals , Diabetes Mellitus, Experimental/drug therapy , Liver , Malate Dehydrogenase/genetics , Plant Extracts/pharmacology , RatsABSTRACT
Enzymatic preparations of two isoforms of succinate dehydrogenase (SDG) with specific activity of 22.00 E/mg of protein were obtained from the colorless sulfur bacterium Sphaerotilus natans D-507 cultured organotrophically. Both SDG forms were shown to be heteromers with subunit molecular masses of 70.8, 35.0, 31.8, and 16.2 kDa. The K(m) values for the first and the second forms of SDG were evaluated as 0.615 and 0.531 mM, respectively, with an optimal pH value of 7.2. It was found that the Cl- ion has an activating effect on the SDG activity that can be explained by the specific chemical modification of the enzyme molecule. The results suggest that the isolated enzyme forms are included in different multienzyme complexes, which provide the functioning of the tricarboxylic acid cycle, and SDG preparations can be used for the investigation of other enzyme systems or in vitro modeling of supramolecular cellular structures.
Subject(s)
Bacterial Proteins/isolation & purification , Protein Subunits/isolation & purification , Sphaerotilus/enzymology , Succinate Dehydrogenase/isolation & purification , Bacterial Proteins/chemistry , Bacterial Proteins/metabolism , Chlorides/chemistry , Chlorides/metabolism , Chromatography, Gel , Citric Acid Cycle/physiology , Electrophoresis, Polyacrylamide Gel , Enzyme Activation , Hydrogen-Ion Concentration , Isoenzymes/chemistry , Isoenzymes/isolation & purification , Isoenzymes/metabolism , Kinetics , Protein Conformation , Protein Multimerization , Protein Subunits/chemistry , Protein Subunits/metabolism , Sphaerotilus/chemistry , Succinate Dehydrogenase/chemistry , Succinate Dehydrogenase/metabolismABSTRACT
A probable mechanism of alteration of the isoenzyme composition of succinate dehydrogenase (SDH) due to differential expression of genes encoding subunit A was considered. The alteration of SDH activity during maize seed germination was investigated, and its maximal activity on day 4-5 of germination was found. The alteration of the sdh1-1 and sdh1-2 gene expression level during maize seed germination was evaluated using the quantitative polymerase chain reaction method. The presence of four forms of the studied enzymes, providing multiple SDH functions was found in maize inflorescence using electrophoresis in polyacrylamide gel.
