Answer to Question #94644 in Biochemistry for R

Question

1) Acetyltransferase enzymes modify a lysine side chain with an acetyl group. Titration of the pKa of the lysine substrate reveals the pKa value to be 8.1. What is the likely environment surrounding the lysine sidechain before it is acetylated? (Choose all that apply)

Cannot hypothesize based on the given information and prior knowledge
Water accessible active site in the enzyme
Water inaccessible highly polar active site
Largely non-polar and water inaccessible active site
Solvent exposed and near the enzyme surface

Answer 1

Water accessible active site in the enzyme

Solvent exposed and near the enzyme surface

Above two options are correct.

Lysine is a positively charged amino acid so it is water soluble. So before acetylation being a hydrophilic amino acid it will be easily accessible to water in the active site and also will be exposed to water near he active site.