Cdc14 phosphatases use an intramolecular pseudosubstrate motif to stimulate and regulate catalysis.

Cdc14 phosphatases are related structurally and mechanistically to protein tyrosine phosphatases (PTPs) but evolved a unique specificity for phosphoSer-Pro-X-Lys/Arg sites primarily deposited by cyclin-dependent kinases. This specialization is widely conserved in eukaryotes. The evolutionary reconfiguration of the Cdc14 active site to selectively accommodate phosphoSer-Pro likely required modification to the canonical PTP catalytic cycle.

Activity of Fatty Acid Biosynthesis Initiating Ketosynthase FabH with Acetyl/Malonyl-oxa/aza(dethia)CoAs.

Fatty acid and polyketide biosynthetic enzymes exploit the reactivity of acyl- and malonyl-thioesters for catalysis. A prime example is FabH, which initiates fatty acid biosynthesis in many bacteria and plants. FabH performs an acyltransferase reaction with acetyl-CoA to generate an acetyl--FabH acyl-enzyme intermediate and subsequent decarboxylative Claisen-condensation with a malonyl-thioester carried by an acyl carrier protein (ACP).