Porin

Part of speech: noun

Definitions

1. A type of protein that forms channels in cell membranes, allowing the passage of small molecules and ions through the lipid bilayer
2. A membrane protein that creates pores in cellular membranes, facilitating the transport of various substances including nutrients and waste
3. A protein that serves as a gateway in the membranes of cells, enabling selective permeability to specific solutes and ions

Etymology: "Porin" is a modern scientific coinage, formed in English by adding the suffix "-in" to "pore". The "-in" ending is a common chemical and biological naming element, used for substances and proteins, and here it marks a protein that forms pores in membranes. The base word "pore" is itself an old English term for a small opening, which fits the job the protein does: porins create tiny channels through the outer membrane of bacteria and other cells, letting small molecules pass in and out. The suffix traces back a long way. Its ultimate ancestors lie in Proto-Indo-European and Proto-Italic forms, which passed into Latin as "-inus", a marker of belonging or substance. It reached English through Old French and Middle English, where it appeared in many adjectives and nouns, before being revived in later chemical terminology. The result is a word assembled from parts that are themselves centuries old, put together for a molecule that nobody knew existed until modern biology described it.

Synonyms: porin protein, membrane channel, beta barrel protein