prefect (plural prefects) 1  An official of Ancient Rome who controlled or superintended a particular command, charge, department, etc. the prefect of the aqueducts; the prefect of a camp, of a fleet, of the city guard, or of provisions; the pretorian prefect, who was commander of the troops guarding the emperor's person.
peptide bond n. The chemical bond formed between the carboxyl groups and amino groups of neighboring amino acids, constituting the primary linkage of all protein structures. peptide bond. The chemical bond formed between amino acids, constituting the primary linkage in all protein structures. In a peptide bond, the carboxyl group (COOH) of one amino acid bonds with the amino group (NH2) of another, forming the sequence CONH and releasing water (H2O).
In this type of structure a hydrogen bond forms between an amino acid and one four amino acids further along the chain. In a perfect alpha-helix, therefore, every peptide bond is hydrogen-bonded to two other peptide bonds in the chain length, but this is rarely the case in natural proteins.