| 释义 |
thiamine|ˈθaɪəmiːn|
[f. thio- + amine.]
†1. Chem. (See quot.) Obs. rare.
1886C. A. Bennert Brit. Pat. 13,466 3 This invention has for its object the manufacture or production of a new class of organic coloring compounds or materials by reactions between certain amines of the aromatic series and the dioxide of sulphur group, which organic colouring compounds or materials so obtained I designate ‘Thiamines’.
†2. Chem. Generic name for amines containing the group NHSH, as ethylthiamine, C2H5.NHSH. Obs. rare.
3. Biochem.
a. Also thiamin. Vitamin B1; a water-soluble, heat-labile, sulphur-containing compound that is present in many foods (esp. whole cereal grains, pork, and liver) but absent from fats and is necessary for carbohydrate metabolism, its dietary deficiency resulting in disturbances of the nervous system.
1937Jrnl. Amer. Med. Assoc. 18 Sept. 952/1 Dr. Jansen has been very cooperative in discussing the matter of nomenclature for vitamin B1 and suggested..that Dr. R. R. Williams..propose a name based on the chemical structure. Dr. Williams..proposed the term Thiamin Chloride. 1939A. Huxley After Many a Summer ii. vi. 234 With a course of thiamin chloride and some testosterone I could have made him as happy as a sand-boy. 1951A. Grollman Pharmacol. & Therapeutics xxvii. 597 Thiamine contains thiazole and pyrimidine rings. 1952New Biol. XIII. 111 The role of thiamin in cell metabolism is to provide a portion of certain enzyme systems. 1972Materials & Technol. V. xix. 674 In Great Britain, all bread except wholemeal must be fortified with thiamin..to compensate for the losses of the natural vitamin consequent on milling. 1980D. Madden Food & Nutrition i. 23/2 After vitamin C, thiamine is probably the most unstable vitamin.
b. thiamine pyrophosphate, the active form of thiamine in which it acts as a co-enzyme: = cocarboxylase.
1949New Biol. VII. 108 These include thiamine pyrophosphate, nicotinamide nucleoside and riboflavine, all of which are involved in systems through which carbohydrates are oxidised. 1960[see diphosphothiamine]. 1973Yudkin & Offord Comprehensive Biochem. (1980) xvii. 297 Transketolase needs as co-factor the vitamin derivative thiamine pyrophosphate, which..is also involved in the transfer of a two-carbon fragment from pyruvate to lipoic acid.
Hence thiˈaminase [-ase], an enzyme that destroys thiamine, splitting the thiazole and the pyrimidine rings.
1938Bonner & Buchman in Proc. Nat. Acad. Sci. XXIV. 437 It has been shown..that the pea root synthesizes vitamin B1..from a mixture of the pyrimidine and thiazole components of the vitamin molecule... This must..be a synthesis in which a specific enzyme, a ‘thiaminase’.., takes part. 1972L. Hancock There's a Seal in my Sleeping Bag ii. 23 Herring is a fish that contains an enzyme called thiaminase, which breaks down thiamin in the body. |