BI3.1-6 | Chemistry and Metabolism of Carbohydrates — Glossary

Polyhydroxy aldehydes or ketones, classified as monosaccharides, disaccharides, or polysaccharides, serving as energy fuel, structural elements, and storage molecules

The universal 10-step cytoplasmic pathway that converts one glucose molecule to two pyruvate molecules, yielding 2 ATP and 2 NADH net

The rate-limiting enzyme of glycolysis that converts F6P to F1,6-BP; activated by AMP and F2,6-BP, inhibited by ATP and citrate

The final common pathway for oxidation of acetyl-CoA in the mitochondrial matrix, generating 3 NADH, 1 FADH2, and 1 GTP per turn

A multienzyme complex that irreversibly converts pyruvate to acetyl-CoA, linking glycolysis to the TCA cycle, requiring five coenzymes (TPP, lipoic acid, CoA, FAD, NAD+)

The synthesis of glucose from non-carbohydrate precursors (lactate, glycerol, amino acids) in the liver and kidney, costing 6 ATP equivalents per glucose

The metabolic cycle where lactate produced by anaerobic glycolysis in muscle is transported to liver for gluconeogenesis, and the resulting glucose returns to muscle

The synthesis of glycogen from glucose, with glycogen synthase as the rate-limiting enzyme, stimulated by insulin

The breakdown of glycogen to G1P by glycogen phosphorylase, stimulated by glucagon (liver) and epinephrine (muscle)

An alternative glucose oxidation pathway producing NADPH for reductive biosynthesis and ribose-5-phosphate for nucleotide synthesis

The rate-limiting enzyme of the HMP shunt that generates NADPH; its X-linked deficiency causes haemolytic anaemia triggered by oxidant drugs and fava beans

Sodium-glucose linked transporter 1 — a secondary active transporter on the intestinal brush border that co-transports glucose and galactose with Na+

The insulin-dependent glucose transporter in muscle and adipose tissue, stored in intracellular vesicles and translocated to the membrane by insulin signalling

A peptide hormone from pancreatic beta-cells that promotes glucose uptake, glycolysis, glycogenesis, and lipogenesis in the fed state

A peptide hormone from pancreatic alpha-cells that promotes glycogenolysis and gluconeogenesis in the fasting state to maintain blood glucose

Haemoglobin non-enzymatically glycated at the N-terminal valine; reflects average blood glucose over 2-3 months, with ≥6.5% diagnostic for diabetes

A life-threatening complication of insulin deficiency (usually Type 1 DM) with hyperglycaemia, ketone body accumulation, and metabolic acidosis

Irreversible products of non-enzymatic protein glycation in chronic hyperglycaemia that cross-link proteins and activate inflammatory pathways via RAGE receptors

The pathway converting glucose to sorbitol (by aldose reductase) then fructose; causes osmotic damage in diabetic lens, nerves, and vessels

An inborn error of galactose metabolism due to galactose-1-P uridylyltransferase deficiency, causing cataracts, hepatomegaly, and intellectual disability

Deficiency of intestinal lactase causing undigested lactose to ferment in the colon, producing bloating, cramps, and osmotic diarrhoea; affects 60-80% of Indian adults

A group of inherited disorders caused by deficient enzymes of glycogen metabolism, including Von Gierke (Type I), Pompe (Type II), and McArdle (Type V)

The observation that cancer cells preferentially use glycolysis even in the presence of oxygen (aerobic glycolysis), the basis for PET-FDG cancer imaging

A cluster of central obesity, hypertension, hyperglycaemia, hypertriglyceridaemia, and low HDL driven by insulin resistance, highly prevalent in South Asians

The most potent allosteric activator of PFK-1 and inhibitor of fructose-1,6-bisphosphatase, serving as the master switch between glycolysis and gluconeogenesis