In conclusion, facilitated by the steadily expanding pool of genome and metagenome sequences, ASR is a useful tool to both find biocatalysts with new reaction fingerprints, which can be accessed via considerably streamlined screening, as well as to understand trends in reaction selectivity and other properties. Fatty acid hydroxylation is an industrially important and chemically challenging target for regioselective C-H activation and ASR has been able to produce biocatalysts with new regioselectivities, compared to natural sequences explored previously. Our findings also provide insights into the structure-function relationships leading to the unique regioselectivity of P450-TT, i.e., a shift towards mid-chain hydroxylation. This approach has provided a library of diverse artificial templates both for the P450 and the reductase domains and some landmarks in the sequence space around these enzymes that can be used as starting points in future protein engineering campaigns to achieve efficient and regioselective C-H hydroxylation.