tetralinoleoyl

Tetralinoleoyl refers to a lipid species carrying four linoleoyl (18:2) fatty acid chains. In practice, the term is most often encountered with cardiolipin, a unique tetraacyl phospholipid found in mitochondrial membranes, where the full descriptor is tetralinoleoyl cardiolipin (TLCL). TLCL is a common cardiolipin species in mammals, defined by having all four acyl chains as linoleate.

Structure and composition: Cardiolipin consists of two phosphatidyl moieties linked by a central glycerol, yielding four fatty acyl chains in total. When all four chains are linoleoyl, the molecule is designated tetralinoleoyl cardiolipin. The four linoleoyl chains influence the lipid’s physical properties and interactions within the mitochondrial inner membrane.

Occurrence and biosynthesis: TLCL is produced and maintained through cardiolipin biosynthesis and remodeling within mitochondria. Remodeling enzymes, notably tafazzin, preferentially replace diverse acyl chains with linoleoyl groups to enrich TLCL in many tissues. Disruptions in remodeling can alter TLCL content and mitochondrial function.

Function and significance: Cardiolipin, including TLCL, helps stabilize respiratory chain supercomplexes, supports cristae morphology, and participates in mitochondrial membrane integrity and dynamics. Changes in TLCL composition are associated with mitochondrial dysfunction and have been studied in the context of metabolic disorders and aging. Barth syndrome, caused by tafazzin deficiency, exemplifies the functional impact of altered TLCL remodeling on mitochondrial biology.

See also: cardiolipin, linoleoyl, tafazzin, Barth syndrome.