<Li> of serine by protein - serine epimerase </Li> <Li> of alanine in dermorphin, a frog opioid peptide </Li> <Li> of methionine in deltorphin, also a frog opioid peptide </Li> <Li> protein splicing, self - catalytic removal of inteins analogous to mRNA processing </Li>

Which of the following is an example of post translational modification