Benders'dictionary of nutrition and food technology

478transferrin The main iron transport protein in plasma. Fractionalsaturation of transferrin with iron provides a sensitive index ofiron status, but transferrin synthesis is impaired in some chronicdiseases, so fractional saturation may be inappropriately high.This also limits the usefulness of transferrin measurement as anindex of protein–energy nutrition. Total iron binding capacity ofplasma is the sum of free plus iron-containing transferrin.transferrin receptor A transmembrane protein for uptake oftransferrin (and hence iron) into cells. The extracellular regionis cleaved and enters the circulation, where it can be measuredby immunoassay. In early iron deficiency there is induction of thetransferrin receptor, and an elevated plasma concentration ofthe extracellular fragment provides a sensitive index of ironstatus.transgenic A micro-organism, plant or animal genetically engineeredto contain a gene from another species. See also AGROBAC-TERIUM TUMEFACIENS; biolistics; genetic modification;electroporation.transient ischaemic attack (TIA) Temporary disruption of theblood supply to part of the brain, due to embolism, thrombosisor a spasm of the arterial wall.transit time The time taken between ingestion of a food and itselimination in faeces, commonly measured by including radioopaqueplastic markers in the test food, followed by X-ray examinationof faeces.transketolase Enzyme (EC 2.2.1.1) in the pentose phosphatepathway of glucose metabolism; requires thiamin diphosphateas cofactor, so activation of apo-transketolase in red blood cellsby thiamin diphosphate added in vitro provides an index ofvitamin B 1 status. An activation coefficient above 1.25 indicatesdeficiency.translation The process of synthesising protein on the ribosome,by translating the information in mRNA into the amino acidsequence.See also transcription.transthyretin thyroid hormone binding protein in plasma, formerlyknown as pre-albumin. Also forms a complex with thesmall plasma retinol binding protein to prevent loss of boundvitamin a by renal filtration. It has a half-life of 2–3 days, andmay provide an index of nutritional status because synthesisdecreases rapidly in protein–energy malnutrition; however, synthesisis also affected by trauma and sepsis.trassi (trassi udang) Sumatran; cured salted shrimp paste; maycontain potato peelings or rice bran. Cooked with chilli peppersto make the condiment sambal goring.