T-3364366 Targets the Desaturase Domain of Delta-5 Desaturase with Nanomolar Potency and a Multihour Residence Time.

ABSTRACT: Delta-5 desaturase (D5D) catalyzes the conversion from dihomo-gamma linoleic acid (DGLA) to arachidonic acid (AA). DGLA and AA are common precursors of anti- and pro-inflammatory eicosanoids, respectively, making D5D an attractive drug target for inflammatory-related diseases. Despite several reports on D5D inhibitors, their biochemical mechanisms of action (MOAs) remain poorly understood, primarily due to the difficulty in performing quantitative enzymatic analysis. Herein, we report a radioligand binding assay to overcome this challenge and characterized T-3364366, a thienopyrimidinone D5D inhibitor, by use of the assay. T-3364366 is a reversible, slow-binding inhibitor with a dissociation half-life in excess of 2.0 h. The long residence time was confirmed in cellular washout assays. Domain swapping experiments between D5D and D6D support [(3)H]T-3364366 binding to the desaturase domain of D5D. The present study is the first to demonstrate biochemical MOA of desaturase inhibitors, providing important insight into drug discovery of desaturase enzymes.

SUBMITTER: Miyahisa I 

PROVIDER: S-EPMC5018866 | biostudies-other | 2016 Sep

REPOSITORIES: biostudies-other