Related Experiment Video
Updated: Aug 12, 2026

The Importance of Correct Protein Concentration for Kinetics and Affinity Determination in Structure-function Analysis
Published on: March 17, 2010
Affinity and hydrophobic interactions of penicillin amidase
Abstract:
Binding of penicillin amidase from E. coli 436 to aniline-, benzylamine- and phenylethylamine-Sepharose was studied. Binding of the enzyme to aniline-Sepharose was exclusively due to hydrophobic interactions. Benzylamine-Sepharose binds the enzyme due to affinity interactions in the absence of ammonium sulphate and due to hydrophobic interactions in the presence of ammonium sulphate. A conformational change in the penicillin amidase molecule due to ammonium sulphate there by exposing the side chain binding site as a hydrophobic core is suggested.
Related Concept Videos
Affinity and Avidity
Ligand Binding Sites
Protein-ligand interactions are quite specific; even though numerous potential ligands surround a cellular protein at any given time, only a particular ligand can bind to that protein. Moreover, a ligand binds only to a dedicated area on the surface of the protein, known as the...
Amides to Carboxylic Acids: Hydrolysis
Acid-catalyzed hydrolysis:
Hydrolysis of amides under acidic conditions yields carboxylic acids. Since the reaction occurs slowly, hydrolysis requires the conditions of heat.
The mechanism begins with the protonation of the carbonyl oxygen by the acid catalyst. The protonation makes the amide carbonyl carbon more...
Basicity of Aliphatic Amines
To measure the basicity of amines, two conventions are generally used. The first defines Kb as the basicity constant for the deprotonation reaction of water by the amine, as presented in Figure 1. Conventionally, lower Kb indicates higher...
Production of Antibiotics
Inhibitors of Gram-positive Cell Wall Synthesis

