Pyruvate dehydrogenase complex

CONTENTS What is the pyruvate dehydrogenase complex? Coenzymes of the pyruvate dehydrogenase complex Where is the pyruvate dehydrogenase complex located? Functions of the pyruvate dehydrogenase complex Other sources of acetyl-CoA Sources of pyruvate Mitochondrial pyruvate transport Structure of the pyruvate dehydrogenase complex Structure of pyruvate dehydrogenase or E1 What is the function of the acidic […]

The pentose phosphate pathway

CONTENTS What is the pentose phosphate pathway? The elucidation of the pentose phosphate pathway Functions of NADPH and ribose 5-phosphate Where does the pentose phosphate pathway occur? The two phases of the pentose phosphate pathway The steps of the oxidative phase of the pentose phosphate pathway The oxidation of glucose 6-phosphate to 6-phosphoglucono-δ-lactone Catalytic mechanism […]

Glycolysis

CONTENTS What is glycolysis? Glycolysis: the first metabolic pathway to be elucidated Why is glycolysis so important? The steps of glycolysis Reaction 1: glucose phosphorylation to glucose 6-phosphate The importance of glucose phosphorylation Other possible fates of glucose 6-phosphate Reaction 2: isomerization of glucose 6-phosphate to fructose 6-phosphate Reaction 3: phosphorylation of fructose 6-phosphate to […]

Gluconeogenesis

CONTENTS What is gluconeogenesis? Why is gluconeogenesis important? Where does gluconeogenesis occur? Irreversible steps of gluconeogenesis From pyruvate to phosphoenolpyruvate Phosphoenolpyruvate precursor: pyruvate or alanine Phosphoenolpyruvate precursor: lactate From fructose 1,6-bisphosphate to fructose 6-phosphate From glucose 6-phosphate to glucose Gluconeogenesis: energetically expensive Coordinated regulation of gluconeogenesis and glycolysis Regulation of gluconeogenesis Pyruvate carboxylase Fructose 1,6-bisphosphatase […]

Glucose-alanine cycle

CONTENTS What is the glucose-alanine cycle? The steps of the glucose-alanine cycle The Cahill cycle in skeletal muscle The Cahill cycle in the liver Transaminases Functions of the glucose-alanine cycle Energy cost of the glucose-alanine cycle Similarities and differences between Cahill cycle and Cori cycle References What is the glucose-alanine cycle? The glucose-alanine cycle, or […]

Cori cycle: definition, function, biochemistry, involved tissues

CONTENTS What is the Cori cycle? Where does the Cori cycle occur? The steps of the Cori cycle Lactate dehydrogenase Other metabolic fates of lactate Energy cost of the glucose-lactate cycle Is the Cori cycle a futile cycle? The Cori cycle and glucose-alanine cycle References What is the Cori cycle? The Cori cycle, or glucose-lactate […]

Digestion of starch and alpha-amylase

Factors affecting relationship between starch and alpha-amylase Amylose and amylopectin, the two families of homopolysaccharides constituting starch, during their biosynthesis within vegetable cells, are deposited in highly organized particles called granules. Granules have a partially crystalline structure and diameter ranging from 3 to 300 µm. The access of the alpha-amylase, the enzyme that catalyzes the […]

Glycogen: an efficient storage form of energy in aerobic conditions

What is the net energy yield for the oxidation of a glucose unit from glycogen in aerobic conditions? In aerobic conditions, the oxidation of a free glucose to CO2 and H2O (glycolysis, Krebs cycle and oxidative phosphorylation) leads to the net production of about 30 molecules of ATP. Glucose from the action of glycogen phosphorylase: glucose-1-phosphate […]

Maltodextrin, fructose and endurance sports

Carbohydrate ingestion can improve endurance capacity and performance. The ingestion of different types of carbohydrates, which use different intestinal transporters, can: increase total carbohydrate absorption; increase exogenous carbohydrate oxidation; and therefore improve performance. Glucose and fructose When a mixture of glucose and fructose is ingested (in the analyzed literature, respectively 1.2 and 0.6 g/min, ratio 2:1, for […]

Glycogen: an efficient storage form of energy in anaerobic conditions

What is the net energy yield for the oxidation of a glucose unit from glycogen in anaerobic conditions? In anaerobic conditions, the oxidation of a free glucose to lactate leads to the net production of two molecules of ATP. Glucose from the action of glycogen phosphorylase: glucose-1-phosphate release (about 90% of the removed units) Glycogen […]

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