Xenometrix rat liver S9 fractions for metabolic activation in Ames mutagenicity and umuC SOS genotoxicity assays.
S9 fraction is prepared from the post-mitochondrial supernatant of rat livers after induction of cytochrome P450 enzymes, providing the Phase I and Phase II metabolic enzymes required to activate promutagens and progenotoxins to their reactive metabolites.
Aroclor 1254-induced S9 is prepared per the standard OECD TG 471 protocol and is recommended for definitive GLP regulatory Ames studies; it provides the broadest spectrum of CYP induction including CYP1A1, CYP1A2, CYP2B1, and CYP2B2. Phenobarbital/beta-naphthoflavone (PB/BNF)-induced S9 is an Aroclor-free alternative for laboratories where Aroclor 1254 (a polychlorinated biphenyl mixture) is restricted; it provides comparable metabolic activation for most standard promutagens.
Both S9 fractions are supplied as 0.5 mL aliquots at defined total protein concentration (validated per batch), with lot-specific 2-aminoanthracene dose-response data confirming activation performance. S9 co-factor solution (MgCl2/KCl/G6P/NADP in sodium phosphate buffer) is available separately --- see S9 Cofactor sub-category --- for S9 mix preparation per OECD TG 471.