Dr. Kevin Ahern and Dr. Indira Rajagopal's electronic book is aimed at helping students learn the basics of biochemistry in a fun and engaging format.
Thumbnail: An enzyme binding site that would normally bind substrate can alternatively bind a competitive inhibitor, preventing substrate access. Dihydrofolate reductase is inhibited by methotrexate which prevents binding of its substrate, folic acid. Binding site in blue, inhibitor in green, and substrate in black(PDB: 4QI9). Image used with permission (CC BY 4.0; Thomas Shafee).