vitamin K
The definitions used in this glossary of terminology either have been provided by the authors of the articles, or have been extracted wholly or in part, or paraphrased from the following sources: The American Medical Association Encyclopedia of Medicine, Charles B. Clayman, MD, Medical Editor, Random House, New York, 1989; Biotechnology from A to Z, 2d Edition, William Bains, Oxford University Press, New York, New York, 2002; A Dictionary of Genetics, 6th Edition, Robert C. King and William D. Stansfield, Oxford University Press, New York, New York, 2002; Dorland's Illustrated Medical Dictionary, 29th and 30th Editions, W. B. Saunders Company, Philadelphia, 2000, 2003; Genes VII, Benjamin Lewin, Oxford University Press, New York, New York, 2000; The Gale Encyclopedia of Genetic Disorders, Volumes I and II, Stacey L. Blachford, Ed., Thomson Learning, New York, New York, 2002; The Merriam-Webster Dictionary, Merriam-Webster, Inc., Springfield, Massachusetts, 1997; Molecular Biology of the Cell, 3rd Edition, Bruce Alberts, et al., Garland Publishing, 1994; The Random House Dictionary of the English Language, Unabridged Edition, 1966; Webster's Ninth New Collegiate Dictionary, 1991.
DEFINITION:
- vitamin K
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Any of a group of structurally similar fat-soluble compounds that promote blood clotting by increasing hepatic biosynthesis of prothrombin and other coagulation factors, activating these factors by y-carboxylation of glutamic acid moieties in inactive precursor proteins. Two forms exist naturally, phytonadione (vitamin K1) and menaquinone (vitamin K2), as well as one synthetic provitamin form, menadione (vitamin K3). The best sources are green leafy vegetables, liver, cheese, butter, and egg yolk, and as menaquinone it is synthesized by the intestinal flora. Deficiency, usually seen only in neonates, in disorders of absorption, or during antibiotic therapy, is characterized by hemorrhage.
Used in 4 Term definitions
Used in 4 Term definitions