Catalyzes the hydrolysis of UDP-3-O-myristoyl-N-acetylglucosamine to form UDP-3-O-myristoylglucosamine and acetate, the committed step in lipid A biosynthesis. a UDP-3-O-[(3R)-3-hydroxyacyl]-N-acetyl-alpha-D-glucosamine + H2O = a UDP-3-O-[(3R)-3-hydroxyacyl]-alpha-D-glucosamine + acetate Glycolipid biosynthesis; lipid IV(A) biosynthesis; lipid IV(A) from (3R)-3-hydroxytetradecanoyl-[acyl-carrier-protein] and UDP-N-acetyl-alpha-D-glucosamine: step 2/6. Belongs to the LpxC family.