3D-QSAR studies of Dipeptidyl peptidase IV inhibitors using a docking based alignment

Dipeptidyl peptidase IV ( DPP- IV) deactivates the incretin hormones GLP- 1 and GIP by cleaving the penultimate proline or alanine from the N- terminal ( P1-position) of the peptide. Inhibition of this enzyme will prevent the degradation of the incretin hormones and maintain glucose homeostasis; this makes it an attractive target for the development of drugs for diabetes. This paper reports 3D- QSAR analysis of several DPP- IV inhibitors, which were aligned by the receptor- based technique. The conformation of the molecules in the active site was obtained through docking methods. The QSAR models were generated on two training sets composed of 74 and 25 molecules which included phenylalanine, thiazolidine, and fluorinated pyrrolidine analogs. The 3D- QSAR models are robust with statistically significant r(2), q(2), and r(2) pred values. The CoMFA and CoMSIA models were used to design some new inhibitors with several fold higher binding affinity.