Emergent Cardiovascular Risk Factor: Homocysteine

Cindy J. Warren, MSN, RN


Prog Cardiovasc Nurs. 2002;17(1) 

In This Article

Homocysteine Metabolism

Homocysteine is a naturally occurring intermediate amino acid formed during the complex metabolism of the amino acid methionine. Homocysteine can either enter the trans-sulfuration pathway to eventually be excreted as a sulfate in the urine, or it can enter the remethylation pathway whenever there is a relative methionine deficiency.[3] The remethylation ability of homocysteine ensures an adequate supply of methionine for protein synthesis.[3] Under normal conditions, about 50% of homocysteine irreversibly enters the trans-sulfuration pathway.[3] The homocysteine concentration in the blood is an important reflection of the status of intracellular methionine metabolism.[3] The metabolic pathway that homocysteine takes can be influenced by alterations in the concentrations of folic acid, vitamin B6, and vitamin B12, and by activities of the various enzymes that participate in metabolic processes.[3] Research correlations have been made that attribute cardiovascular or peripheral vascular occlusive disease to elevations of plasma homocysteine.[1,2,3,4,5,6,7]


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