Question

What types of modifications can occur after a polypeptide chain has been completed by a ribosome? (Choose as many that apply)

A) Glycosylation

B) Removal of methionine

C) Hydrolysis

D) Addition of amino acids

E) Phosphorylation

Answer 1

The modifications that are brought about in a translated polypeptide are called post translational modifications.

These include:

• Glycosylation : Addition of glucose group to the amino acid resulting in formation of glycoproteins
• Removal of methionine : Initiator methionine can be removed from translated polypeptide.
• Hydrolysis : Proteolysis of translated chain involves hydrolysis of peptide bond.
• Addition of amino acids : Addition of amino acids such as arginine, glycine etc occurs in certain cases.
• Phosphorylation : Amino acids like serine, threonine etc can undergo addition of phosphate group.

So, all these options are correct