What is the difference between the A2I database for mutagenicity and the A2K-A2Z databases?
The A2I database gives a measure of global mutagenicity in all strains of S. Typhimurium. It is a binary database, in which chemicals are classified categorically as active or inactive, without considering mutagenic potency. This means that a chemical that is very highly mutagenic in the Ames test is considered to be no more active than a chemical that is only moderately mutagenic. The A2K-A2Z databases correspond to mutagenicity in five separate strains of S. Typhimurium (TA97, TA98, TA100, TA1535, TA1537). The databases are further separated on the basis of presence or absence of metabolic activation (S-9). Activities of chemicals in the A2K-A2Z modules are based on a continuous scale of mutagenic potency, ranging from 10 CASE units (nonmutagenic) to 80 CASE units (very highly mutagenic). This means that screening a chemical against the A2K-A2Z modules can provide detailed information about mechanism and mutagenic potency, while the A2I module gives a yes or no decision about mutagen
