[Recent discoveries on the biochemical significance of vitamin K and some characteristics of vitamin K dependent proteins].
Vitamin K1 and K2 as well as menadione are in the cells for the largest part transformed into 2-methyl-3-geranylgeranylnaphthoquinone which is hydrated to hydroquinone and which is a constituent of the carboxylase system. By means of this enzyme system in the precursors of the coagulation factors II, VII, IX, and X the proportions of carboxyglutamate are changed into proportions of gamma-carboxyglutamate. Through these proportions of gamma-carboxyglutamate these coagulation factors may be enriched at phospholipid membranes with participation of Ca-ions in the area of injuries of vessels, by means of which the blood coagulation is locally much furthered. By dicoumarol and warfarin this carboxylation is much inhibited and at the same time the degradation of the K-vitamins is much stimulated, the vitamin K content in the liver decreases. The vitamin K depending carboxylase system occurs also in the rough endoplasmatic reticulum of lung, nerve, bone and kidney cells. In the bone cells its participates in the formation of the gamma-carboxyglutamate containing osteocalcin which is of importance for the mineralisation of the bones. Proteins containing gamma-carboxyglutamate were proved also in ribosomes.
D015055:1-Carboxyglutamic Acid / Q000378:metabolism; D000328:Adult; D001779:Blood Coagulation Factors / Q000378:metabolism; D002113:Calcification, Physiologic / Q000187:drug effects; D006801:Humans; D014812:Vitamin K / Q000378:metabolism* / Q000494:pharmacology / Q000502:physiology; D010837:Vitamin K 1 / Q000378:metabolism
D001779:Blood Coagulation Factors; D014812:Vitamin K; D015055:1-Carboxyglutamic Acid; D010837:Vitamin K 1
Neuere Erkenntnisse über die biochemische Bedeutung der K-Vitamine und über einige Eigenschaften der vitamin-K-abhängigen Proteine.