Adds a myristoyl group to the N-terminal glycine residue of certain cellular proteins. Can also use decanoyl-CoA and lauroyl-CoA as substrates. N-terminal glycyl-[protein] + tetradecanoyl-CoA = CoA + H(+) + N-tetradecanoylglycyl-[protein] Optimum pH is 7.8. Active from pH 5.5 to 8.5. Mostly associated to ribosomes. Present to a lower extent in mitochondria. Expressed ubiquitously, with higher levels in young tissues (at protein level). Belongs to the NMT family.