Derek Lowe writes about the "hot" field of activity-based protein profiling, which he explains via a critique of a current paper out of Benjamin Cravatt's lab at Scripps. His paper tested the most effective ways to photoaffinity-label histone deacetylase enzymes and found that in vitro and in vivo results are not always the same. Lowe emphasizes that in drug discovery especially, assumptions should never be made. "If you say 'in vitro', I say 'whole cells'. If you've got it working in cells, I'll call for mice. Then I'll see your mice and raise you some dogs. Get your compounds as close to reality as you can before you pass judgment on them,” he writes at In the Pipeline.