Enzymes & cofactors

Search by name, gene symbol, EC number or the disorder it causes. Open any enzyme to see every reaction it catalyses, what accelerates it and what inhibits it.

Enzymes Cofactor terms Vitamins & minerals

Vitamin and mineral cofactors

Active form, the enzymes that depend on it, and what deficiency looks like

17 entries

B1 (Thiamine)

Thiamine pyrophosphate (TPP) unreviewed

Dependent enzymes

PDC, alpha-ketoglutarate dehydrogenase, BCKDH, transketolase

Deficiency

Beriberi (wet/dry), Wernicke-Korsakoff; raised lactate

Lab marker

Erythrocyte transketolase activity

B2 (Riboflavin)

FMN, FAD unreviewed

Dependent enzymes

Complex I and II, acyl-CoA dehydrogenases, glutathione reductase, MTHFR

Deficiency

Angular cheilitis, glossitis, corneal vascularisation

Lab marker

—

B3 (Niacin)

NAD+, NADP+ unreviewed

Dependent enzymes

Glycolysis, TCA, beta-oxidation, PPP, all dehydrogenases

Deficiency

Pellagra: dermatitis, diarrhoea, dementia; also in Hartnup disease and carcinoid

Lab marker

—

B5 (Pantothenic acid)

Coenzyme A, ACP unreviewed

Dependent enzymes

TCA (succinyl-CoA), beta-oxidation, fatty acid synthesis

Deficiency

Dermatitis, enteritis, adrenal insufficiency, paraesthesia

Lab marker

—

B6 (Pyridoxine)

Pyridoxal phosphate (PLP) unreviewed

Dependent enzymes

Transaminations, decarboxylations, SHMT, glycogen phosphorylase, ALA synthase, CBS

Deficiency

Sideroblastic anaemia, peripheral neuropathy, seizures, cheilosis; isoniazid depletes B6

Lab marker

—

B7 (Biotin)

Biocytin unreviewed

Dependent enzymes

Carboxylases: ACC, pyruvate carboxylase, propionyl-CoA carboxylase, methylcrotonyl-CoA carboxylase

Deficiency

Dermatitis, alopecia, enteritis; caused by avidin in raw egg white or by long antibiotics

Lab marker

—

B9 (Folate)

Tetrahydrofolate (THF) unreviewed

Dependent enzymes

One-carbon metabolism, purine synthesis, dTMP synthesis

Deficiency

Megaloblastic anaemia WITHOUT neurological signs; neural tube defects

Lab marker

Serum/RBC folate; homocysteine raised, MMA normal

B12 (Cobalamin)

Methylcobalamin, adenosylcobalamin unreviewed

Dependent enzymes

Methionine synthase, methylmalonyl-CoA mutase

Deficiency

Megaloblastic anaemia WITH subacute combined degeneration; methyl-folate trap

Lab marker

Homocysteine AND methylmalonic acid both raised

C (Ascorbate)

Ascorbic acid unreviewed

Dependent enzymes

Collagen prolyl/lysyl hydroxylase, dopamine beta-hydroxylase, iron absorption

Deficiency

Scurvy: perifollicular haemorrhage, corkscrew hairs, bleeding gums, poor wound healing

Lab marker

—

D (Cholecalciferol)

1,25-(OH)2-D3 (calcitriol) unreviewed

Dependent enzymes

Calcium and phosphate homeostasis, gene transcription via VDR

Deficiency

Rickets in children, osteomalacia in adults

Lab marker

Serum 25-OH-D

E (Tocopherol)

alpha-Tocopherol unreviewed

Dependent enzymes

Chain-breaking antioxidant in membranes

Deficiency

Haemolytic anaemia, ataxia, peripheral neuropathy

Lab marker

—

K (Phylloquinone/menaquinone)

Vitamin K hydroquinone (KH2) unreviewed

Dependent enzymes

gamma-Carboxylation of factors II, VII, IX, X and proteins C, S, Z

Deficiency

Bleeding, haemorrhagic disease of the newborn; warfarin blocks recycling

Lab marker

PT/INR

Selenium

Selenocysteine unreviewed

Dependent enzymes

Glutathione peroxidase, thioredoxin reductase, deiodinases

Deficiency

Cardiomyopathy (Keshan disease)

Lab marker

—

Magnesium

Mg2+ unreviewed

Dependent enzymes

Nearly all kinases and ATP-dependent enzymes

Deficiency

Tetany, arrhythmia, refractory hypokalaemia and hypocalcaemia

Lab marker

—

Iron

Fe2+/Fe3+, heme, Fe-S clusters unreviewed

Dependent enzymes

Ferrochelatase, ETC complexes, aconitase, catalase, hydroxylases

Deficiency

Microcytic hypochromic anaemia; overload causes haemochromatosis

Lab marker

—

Copper

Cu unreviewed

Dependent enzymes

Cytochrome c oxidase, lysyl oxidase, dopamine beta-hydroxylase, superoxide dismutase

Deficiency

Menkes (deficiency, kinky hair), Wilson disease (overload)

Lab marker

—

Zinc

Zn2+ unreviewed

Dependent enzymes

Carbonic anhydrase, alcohol dehydrogenase, matrix metalloproteinases, zinc-finger factors

Deficiency

Acrodermatitis enteropathica, hypogonadism, poor wound healing, dysgeusia

Lab marker

—