A substance having the power of contracting organic tissue.

A molecule or cell which physically transports a molecular substance, such as oxygen or (in immunology) a hapten.

Any enzyme which catalyses a reaction by which a specific luciferin produces light.

Any substance which is present naturally in an organism (such as the glow-worm) and which when oxidized in the presence of a specific enzyme (a…

An enzyme produced in bacteria and certain plants which converts urea into carbon dioxide and ammonia.

Any of a large class of iron-containing enzymes which catalyse the oxidation of a substrate by a peroxide (usually hydrogen peroxide).

An enzyme that degrades proteins or polypeptides by hydrolysing peptide bonds; a peptidase. Cf. proteinase, n.

Physiology. A proteolytic enzyme produced by the juxtaglomerular cells of the kidney, which acts to convert angiotensinogen to angiotensin.

Any of a class of copper-containing enzymes, found esp. in plants and arthropods, which oxidize phenols to quinones. Also called phenoloxidase.

An enzyme that degrades proteins by hydrolysing peptide bonds; spec. one that shows specificity for intact proteins, an endopeptidase. Cf. protease…

Any of a class of enzymes found esp. in cereals and yeast which convert phytic acid to myo-inositol and phosphoric acid.

= phospholipase, n.

An enzyme which promotes the conversion of uric acid into allantoin and is found in certain insects and most mammals other than primates.

Any of a group of enzymes which bring about the synthesis or hydrolysis of esters of phosphoric acid, usually in a specified (acid or alkaline)…

An enzyme which hydrolyses β-glucosides (notably prunasin), liberating glucose, and occurs chiefly in bitter almonds and yeast, as well as in the…

= phenolase, n.

A mammalian pituitary hormone that stimulates contraction of the smooth muscle of the uterus and the milk ducts, a synthetic form of which is used to…

Any of a group of enzymes which bring about the hydrolysis of terminal phosphate groups from organic molecules; a phosphatase.

Any of a group of naturally occurring hormones and synthetic compounds that are capable of regulating sexual development in vertebrates, particularly…

Any of a group of enzymes which bring about phosphorolysis, as in the breakdown of glucose polysaccharides to produce glucose phosphate. Frequently…

any of a group of substances that cause slow contraction of smooth muscle; spec. (more fully slow-reacting substance of anaphylaxis) such a…

Any of a group of enzymes which bring about the hydrolysis of ester bonds in phospholipids; (in early use esp.) an enzyme which hydrolyses…

A proteolytic enzyme which destroys blood clots by breaking down fibrin.

a polypeptide stimulating the action of the visceral muscles.

Any enzyme that catalyses the reduction of a nitro group, usually to an amino group, in an organic molecule (typically as part of a…

A cytostatic agent.

An agent that causes or initiates oncogenesis.

A substance causing autoinduction; esp. an extracellular molecule produced by a population of microorganisms which induces a particular process in…