Ames Express™ Strains
The Internal P450 1A2 Bioactivation System based on recombinant human P450 enzymes
The EBPI 777/2205 has a hisD3052 mutation, a -1 frameshift mutation which affects the reading frame of a repetitive -C-G-C-G-C-G-C-G- sequence on the hisD gene. The hisD gene encodes histidinol dehydrogenase, an enzyme involved in the terminal step of histidine biosynthesis. EBPI 777 also contains a bicistronic protein expression vector, pP4501A2-red, which contains human cytochrome P450 1A2 and human NADPH-P450 reductase cDNA. The recombinant expression of these two proteins helps in the bioactivation of drug and foreign compounds into DNA-reactive mutagens. The co-expression of NADPH-P450 reductase with P450 1A2 increases the bioactivation level of the system. This system acts as an in vitro mimic involving the uptake and breakdown of xenobiotic compounds by a mammal and its liver enzymes, resulting in the generation of mutagenic products inside the living system.
EBPI Ames Express bacterial strains; expression of P450 1A2 and NADPH-P450 reductase
TA1538 | hisD3052 | -1 Frameshift | Recombinant Expression of P450 1A2 |
TA98 | hisD3052 | -1 Frameshift | Recombinant Expression of P450 1A2 |
TA100 | hisG46 | Base-Pair Substitution | Recombinant Expression of P450 1A2 |
Educational Applications Click here to learn more about the role of the Ames ExpressTM Strains for educational use. |
Environmental Applications Click here to download EBPI's Ames Express Strain Environmental Handout. |
Medical Applications Click here to learn more about the role of the P450 1A2 in the metabolizing of drug compounds. |
Another advantage with the recombinant P450 1A2 and NADPH-P450 reductase expression system is that the reactive metabolites will be generated inside the cell rather than outside the cell, as is seen with the S9 rat liver mix. As a result, this mode of bioactivation will allow short half-life reactive mutagens enough time to reach DNA sites allowing for an increase in sensitivity to mutagenesis.
The recombinant P450 protein also serves as a cost effective and animal friendly alternative to the S9 rat liver extract mix which is the current bioactivation standard.
Metabolically Activates Carcinogens:
MeIQ, Hetrocyclic amine, Alfatoxin B1
2-Amino-1-methyle-6-phenylimidazo (4,5-b) pyridine (PhIP)
3-Methyl-2-methylaminoimidazo (4,5-f)quinoline (IQ)
Polycyclic Aromatic Hydrocarbons (PAH)
The Ames ExpressTM System:
This system acts as an in vitro mimic involving the uptake and breakdown of xenobiotic compounds by a mammal and its liver enzymes, resulting in the generation of mutagenic products inside the living system. The recombinant P450 1A2 protein also serves as a cost effective and animal friendly alternative to the S9 rat liver extract mix which is the current bio-activation standard . Like EBPI`s GST expressing strains, the recombinant P450 1A2 reductase expression system is that the reactive metabolites will be generated inside the cell rather than outside the cell. As a result, this mode of bioactivation will allow short half-life reactive mutagens enough time to reach DNA sites allowing for an increase in sensitivity to mutagenesis.
P450 1A2 is a Phase 1 enzyme found primarily in the hepatic tissue and is responsible for metabolizing polyaromatic hydrocarbons (PAHs), aromatic amines and nitro aromatics. It performs a variety of chemical reactions on several different xenobiotic classes and is a key contributor to the mechanistic mutagenicity of well known carcinogens like benzo(a)pyrene (B[a]P), PhIP and 4-aminobiphenyl.
Click Here for information on GST T1-1 Ames Express Bacterial Strains.
Potential Applications:
- Testing of pharmaceuticals for mutagenic activity
- Testing of industrial effluents for presence of possible mutagenic compounds
- Screening of municipal discharges for possible routine presence or spills of mutagenic compounds
- Screening of surface and/or groundwater for mutagenic residues
- Screening of potable water supplies for the presence of chemicals with mutagenic potential
- Screening of water soluble air pollutants for mutagenic agents
- Evaluation of pure or complexed raw mixtures for potential mutagenicity
- A convenient and easy to use teaching tool for university and college laboratories