Inhibition of P-enolpyruvate carboxykinase and of glyconeogenesis in Tetrahymena by 3-mercaptopicolinic acid. 1976

T Liang, and G J Raugi, and J J Blum

Tetrahymena grown overnight in deep cultures were incubated for 1 hr with [1-14C]labeled substrates in the presence or absence of 3-mercaptopicolinic acid (3MPA). 3-MPA inhibited appearance of label in glycogen from bicarbonate, acetate, pentanoate, octanoate, and succinate, but not from glycerol or glucose. In vitro assays of phosphoenolpyruvate carboxylase and phosphoenolpyruvate carboxykinase activity showed that both enzymes were about equally distributed between the particulate and cytosol fractions. 3-MPA inhibited phosphoenolpyruvate carboxykinase from both the cytoplasmic and particulate fractions, but had no effect on phosphoenolpyruvate carboxylase from either location. These results suggest that the in vivo effects of this drug are due to inhibition of glyconeogenesis at this site.

UI MeSH Term Description Entries
D010729 Phosphoenolpyruvate Carboxykinase (GTP) An enzyme of the lyase class that catalyzes the conversion of GTP and oxaloacetate to GDP, phosphoenolpyruvate, and carbon dioxide. This reaction is part of gluconeogenesis in the liver. The enzyme occurs in both the mitochondria and cytosol of mammalian liver. (From Dorland, 27th ed) EC 4.1.1.32. GTP-Dependent Phosphoenolpyruvate Carboxykinase,Carboxykinase, GTP-Dependent Phosphoenolpyruvate,GTP Dependent Phosphoenolpyruvate Carboxykinase,Phosphoenolpyruvate Carboxykinase, GTP-Dependent
D010848 Picolinic Acids Compounds with general formula C5H4N(CO2H) derived from PYRIDINE, having a carboxylic acid substituent at the 2-position. Acids, Picolinic
D002262 Carboxy-Lyases Enzymes that catalyze the addition of a carboxyl group to a compound (carboxylases) or the removal of a carboxyl group from a compound (decarboxylases). EC 4.1.1. Carboxy-Lyase,Decarboxylase,Decarboxylases,Carboxy Lyase,Carboxy Lyases
D005947 Glucose A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement. Dextrose,Anhydrous Dextrose,D-Glucose,Glucose Monohydrate,Glucose, (DL)-Isomer,Glucose, (alpha-D)-Isomer,Glucose, (beta-D)-Isomer,D Glucose,Dextrose, Anhydrous,Monohydrate, Glucose
D005990 Glycerol A trihydroxy sugar alcohol that is an intermediate in carbohydrate and lipid metabolism. It is used as a solvent, emollient, pharmaceutical agent, or sweetening agent. 1,2,3-Propanetriol,Glycerin,1,2,3-Trihydroxypropane,Glycerine
D006003 Glycogen
D000085 Acetates Derivatives of ACETIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain the carboxymethane structure. Acetate,Acetic Acid Esters,Acetic Acids,Acids, Acetic,Esters, Acetic Acid
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D001639 Bicarbonates Inorganic salts that contain the -HCO3 radical. They are an important factor in determining the pH of the blood and the concentration of bicarbonate ions is regulated by the kidney. Levels in the blood are an index of the alkali reserve or buffering capacity. Bicarbonate,Bicarbonate Ions,Hydrogen Carbonates,Bicarbonate Ion,Carbonic Acid Ions,Hydrogen Carbonate,Carbonate, Hydrogen,Carbonates, Hydrogen,Ion, Bicarbonate,Ions, Bicarbonate,Ions, Carbonic Acid
D013438 Sulfhydryl Compounds Compounds containing the -SH radical. Mercaptan,Mercapto Compounds,Sulfhydryl Compound,Thiol,Thiols,Mercaptans,Compound, Sulfhydryl,Compounds, Mercapto,Compounds, Sulfhydryl

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