Adds a myristoyl group (tetradecanoyl group) to the N-terminal glycine residue of certain cellular proteins (Probable). Such protein modification are critical for the developmental processes that involve cell shape changes and movement (PubMed:11139338). N-terminal glycyl-[protein] + tetradecanoyl-CoA = CoA + H(+) + N-tetradecanoylglycyl-[protein] Mutant embryos show disrupted actin cytoskeleton and abnormal cell morphology (PubMed:11139338). The range of phenotypes includes head involution failure, dorsal closure, and germ-band retraction, as well as widespread ectopic apoptosis (PubMed:11139338). Belongs to the NMT family.