This article contains a list of restriction enzymes whose names start with A and have a clearly defined cutting site. The following information is given for each enzyme: * Name of Restriction Enzyme: Accepted name of the molecule, according to the internationally adopted nomenclature, and bibliographical references. Note: When alphabetizing, enzymes are first ordered alphabetically by the acronyms (everything before the roman numeral); then enzymes of a given acronym are ordered alphabetically by the roman numeral, treating the numeral as a number and not a string of letters. This helps keep the entries ordered hierarchically while also alphabetic.(Further reading: see the section "Nomenclature" in the article "Restriction enzyme".) * PDB code: Code used to identify the structure of a pr