izoprenoida

Izoprenoida are a large and diverse class of natural products derived from the five-carbon isoprene unit. They are built from the universal building blocks isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP), which are produced by two main biosynthetic pathways: the mevalonate pathway, common in animals, fungi, and many bacteria, and the methylerythritol phosphate (MEP) pathway, present in most bacteria and in plant plastids. Through successive condensations, IPP and DMAPP form longer prenyl diphosphates that are then tailored by terpene synthases and other enzymes to yield thousands of compounds.

Major groups include terpenes (and their oxygenated derivatives, terpenoids) of varying lengths such as monoterpenes (C10), sesquiterpenes (C15), and diterpenes (C20); carotenoids (C40 pigments like beta-carotene and lycopene); steroids and sterols derived from the triterpene squalene; and quinones such as ubiquinone and plastoquinone that participate in electron transport. Tocopherols (vitamin E) are also isoprenoid derivatives. In archaea, isoprenoid chains form ether-linked lipids that are important for membrane structure, and isoprenoids also function as prenyl anchors for various proteins.

Functions and significance encompass ecological roles in aromas, flavors, pollinator attraction, and defense, as well as physiological roles in signaling and metabolism. In plants, terpenoids include important hormones and regulators such as gibberellins and abscisic acid; in animals, isoprenoids contribute to cholesterol, steroid hormones, and electron-carrier molecules. Industrially, izoprenoida are valued for fragrances (such as limonene and pinene), nutraceuticals (β-carotene, tocopherols), medicines, and as components of cosmetics and dietary supplements.