Post-translational Modifications of Proteins

Question 1

Phosphorylation

Answer 1

• Add phosphate group on the side chain of AA.
• May increase or decrease functional activity
• serine, threonine or tyrosine

Question 2

Hydroxylation

Answer 2

• A hydroxyl group (OH)
• Can effect protein stability and protein-protein interaction

Question 3

Methylation

Answer 3

Add methyl (CH3) group

Question 4

Acetylation

Answer 4

• Add acetyl group
• i.e. Histone (DNA structure)
• increase/decrease transcription (methylation)

regulates gene expression (acetylation)

Question 5

Trimming

Answer 5

Trypsinogen into trypsin

Question 6

Lipidation

Answer 6

• Add lipid
• increasing their binding affinity to biological membranes (cell and organelle membranes)

Question 7

Glycosylation

Answer 7

• Add glycan (carbohydrate, polysaccharide)
• May effect cell-cell adhesion and communication