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MYRISTOYLATED PROTEINS

 

 

The first proteins to be demonstrated to contain myristic acid were calcineurin B (Aitken A et al., FEBS Lett 1982, 150, 314) and the catalytic subunit of the cyclic AMP-dependent protein kinase (Carr SA et al., Proc Natl Acad Sci USA 1982, 79, 6128).
It was shown that myristic acid (R2) was attached through an amide linkage to the
a-amino group of glycine (R1) at the N-terminus of both proteins :

R1--NH--CO--R2

Later, a wide range of proteins of viral and cellular origin have been shown to be modified by acylation with myristic acid (Olson EN, Prog Lipid Res 1988, 27, 177).

Myristoylated proteins are localized to the cytosol or to cellular membranes and sometimes to both. Membrane-bound myristoylated proteins interact tightly with the bilayer so that drastic conditions may be used to release them from membranes (Olson EN et al., J Biol Chem 1986, 261, 2458). It is now well established that myristoylation is able to direct soluble proteins to membranes but the specificity of targeting remains unclear.
The function for myristoylation is also not well known. It was speculated that these proteins may represent enzymes involved in lipid metabolism or carrier proteins.