Problem:
Question: Which of the following choices does not describe a type of posttranslational modification of proteins?
a. Precursor proteins are cleaved and trimmed by protease enzymes to produce a functional protein.
b. Amino acids in the amino terminal of the protein can be acetylated.
c. Molecular chaperones help proteins fold correctly.
d. The amino terminal methionine may be removed.
Glycoproteins are produced by the attachment of phosphates to newly synthesized proteins.
Please Explain don't just write the answer.