assay repository PubChem PubChem (http://pubchem.ncbi.nlm.nih.gov) is a public database that contains high throughput screening (HTS) data, where the assays are performed to identify small molecules effective at modulating a given biological process or disease state. The bioactivity results in PubChem are contributed by several organizations, with the majority of data coming from the screening center network under the NIH Molecular Libraries Program (MLP).