Definition
noun, plural: transmembrane proteins
A protein that spans the entire biological membrane.
Supplement
Transmembrane proteins may be classified in two major groups:
- Alpha-helix – present in all types of biological membranes.
- Beta barrel – present in outer membranes of Gram-negative bacteria, cell wall of Gram-positive bacteria, outer membranes of mitochondria and chloroplasts.
Word origin: L, comb. form of trāns (adv. and prep.) across, beyond, through + -membrane.
Acronym: TM.
See also: porin, ion channel.
