After being transported to the liver for degradation, the free fatty acids are coupled to CoA and then catabolized via the beta oxidation pathway. The common phenomenon that drives the folding of both proteins and DNA is hydrophobic effect . The amino acid sequence of a single polypeptide is known as its primary structure. If the subunit structure of an enzyme is said to be a2b2, this is describing the quaternary level of protein structure. In the citric acid cycle, fumarase catalyses the interconversion of fumarate and malate.
Proteins can modulate the properties of ligands to which they bind.
For instance heme in solution would not make a good oxygen carrier because it binds too tightly to CO , but when myoglobin binds the heme protein residues are present that change the relative affinity of myoglobin for oxygen and the molecule against which oxygen competes. However the side chains of these amino acids do not bring enough chemical diversity to catalyze all of the kinds of reactions that enzymes catalyze. In the graph to the right the free energies of A and B are shown. The first is for the reaction without enzyme present and the second is the same reaction in the presence of an enzyme specific for that reaction. Enzymes are remarkable.