Alpha-tocopherol transfer protein (α-TTP) (α-TTP)

Alpha-tocopherol transfer protein (α-TTP) is a 32 kDa cytosolic protein primarily expressed in the liver that serves as the master regulator of systemic vitamin E concentrations (Source: UniProt P49638). Its primary biological function is the selective binding of alpha-tocopherol and its subsequent loading into very-low-density lipoproteins (VLDL) for secretion into the blood (Source: PubMed PMID: 15753140). This process is essential because it prevents the rapid metabolism and excretion of vitamin E, maintaining the antioxidant defenses of the central nervous system and retina. Mutations in the TTPA gene lead to Ataxia with Vitamin E Deficiency (AVED), a rare autosomal recessive disorder characterized by progressive neurodegeneration and vision loss (Source: NIH GeneReviews). In the context of pharmacology, α-TTP is often categorized as a non-therapeutic transport interaction because while it binds and transports alpha-tocopherol, it is not typically the primary site of action for therapeutic drug inhibition (Source: DrugBank). Instead, it is the functional target for vitamin E replacement therapy, where high-dose supplementation is used to overcome transport deficiencies (Source: PubMed PMID: 22491499).

Other names

TTPATTP1Alpha-TTPTocopherol (alpha) transfer proteinAVED

Facilitates the selective transfer of alpha-tocopherol from hepatocytes into very-low-density lipoproteins (VLDL) for systemic circulation.