People who inherit a particular version of the gene CYP2D6 don't get help from standard doses of the pain reliever codeine and can suffer side effects from many other medications. The problem is a sluggish drug-detoxifying enzyme from the cytochrome P450 family. This database from molecular biologist David Nelson of the University of Tennessee, Memphis, can help researchers get a handle on this sprawling group of enzymes, which take part in everything from breaking down Prozac and caffeine to synthesizing cholesterol.
The site lists more than 4000 versions of cytochrome P450 enzymes gleaned from published genomes of humans, honeybees, slime molds, bacteria, and other creatures. The sequences come in standard format, so you can plug them directly into genome analysis software or compare your sequences to those already on the site. For more information about cytochrome P450s, check out transcripts of Nelson's lectures or take a guided tour of some P450 molecules.