Structures of human acetylcholinesterase in complex with dihydrotanshinone I and with territrem B are available (4M0E, 4M0F) and published by Cheung et al. Structures of carboxylesterase Cest-2923 from Lactobacillus plantarum are published by Benavente et al. and will be available soon (4BZW, 4BZZ, 4C01)