Concept #1: Post Translational Modification

Concept #2: Proteolytic Cleavage

Practice: Which of the following would not be a reversible post-translational modification?

Practice: An enzyme’s active site has high affinity for a polar charged substrate. How will methylation of the active site affect the reaction rate of the enzyme?

Practice: Histones are proteins that regulate gene expression by binding to DNA and controlling which regions are exposed to be expressed. Histones bind to DNA at a neutral pH via their positively charged lysine residues, but acetylation of histones leads to the dissociation of the DNA-Histone complex. Covalent modification of lysine’s ammonium group by acetylation results in an overall _______________ charge of the histone binding region.