Inhibition of dipeptidyl-peptidase IV catalyzed peptide truncation by Vildagliptin ((2S)-{[(3-hydroxyadamantan-1-yl)amino]acetyl}- pyrrolidine-2-carbonitrile) Inger Brandt a , Jurgen Joossens b , Xin Chen c , Marie-Berthe Maes a , Simon Scharpe ´ a , Ingrid De Meester a , Anne-Marie Lambeir a, * a Laboratory of Medical Biochemistry, Department of Pharmaceutical Sciences, University of Antwerp, Drie Eiken Campus, Universiteitsplein 1 building S6 B-2610 Antwerpen (Wilrijk), Belgium b Laboratory of Medicinal Chemistry, Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp, Belgium c Division of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Nankang, Taipei, Taiwan, ROC Received 25 February 2005; accepted 14 April 2005 Abstract Vildagliptin (NVP-LAF237/(2S)-{[(3-hydroxyadamantan-1-yl)amino]acetyl}-pyrrolidine-2-carbonitrile) was described as a potent, selective and orally bio-available dipeptidyl-peptidase IV (DPP IV, EC 3.4.14.5) inhibitor [Villhauer EB, Brinkman JA, Naderi GB, Burkey BF, Dunning BE, Prasad K, et al.1-[[(3-Hydroxy-1-adamantyl)amino]acetyl]-2-cyano-(S)-pyrrolidine: a potent, selective, and orally bioavailable dipeptidyl peptidase IV inhibitor with antihyperglycemic properties. J Med Chem 2003;46:2774–89]. Phase III clinical trials for the use of this compound in the treatment of Type 2 diabetes were started in the first quarter of 2004. In this paper, we report on (1) the kinetics of binding, (2) the type of inhibition, (3) the selectivity with respect to other peptidases, and (4) the inhibitory potency on the DPP IV catalyzed degradation of glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP) and substance P. Vildagliptin behaved as a slow-binding DPP IV inhibitor with an association rate constant of 1.4  10 5 M 1 s 1 and a K i of 17 nM. It is a micromolar inhibitor for dipeptidyl-peptidase 8 and does not significantly inhibit dipeptidyl-peptidase II (EC 3.4.11.2), prolyl oligopeptidase (EC 3.4.21.26), aminopeptidase P (EC 3.4.11.9) or aminopeptidase M (EC 3.4.11.2). There was no evidence for substrate specific inhibition of DPP IV by Vildagliptin or for important allosteric factors affecting the inhibition constant in presence of GIP and GLP-1. # 2005 Elsevier Inc. All rights reserved. Keywords: Dipeptidyl-peptidase IV; LAF237; GLP-1; GIP; Substance P; Protease inhibitor 1. Introduction Dipeptidyl-peptidase IV/CD26 (DPP IV/CD26; EC 3.4.14.5) belongs to the prolyl oligopeptidase family of serine proteases. It cleaves off the N-terminal dipeptide from peptides with proline or alanine in the second posi- tion. Although DPP IV is an extracellular membrane protein it is also found in human plasma in a soluble form lacking the transmembrane region. The expression of DPP IV on the surface of differentiated cell types in endothelia, epithelia, and the hematopoietic system has been reviewed [1]. The disease cluster known as the ‘metabolic syndrome’ comprises a number of disorders including type 2 diabetes, arterial hypertension, dyslipidemia and obesity. The cur- rent treatments of type 2 diabetes are unsatisfactory in terms of prevention of complications and preservation of quality of life. The sulfonylureas and the newer class of glinides (e.g. repaglinide) both suffer from inducing hypo- glycemia. The stimulation of insulin secretion induced by prolonging the half-life of endogenous GLP-1 (as achieved with DPP IV inhibitors) is a more physiological approach to increase insulin secretion. The only therapeutic agent www.elsevier.com/locate/biochempharm Biochemical Pharmacology 70 (2005) 134–143 Abbreviations: DPP, dipeptidyl-peptidase; GLP-1, glucagon-like pep- tide-1; GIP, glucose-dependent insulinotropic polypeptide; PO, prolyl oli- gopeptidase; pNA, para-nitroaniline; DTT, dithiothreitol * Corresponding author. Tel.: +32 3 8202727; fax: +32 3 8202734. E-mail address: anne-marie.lambeir@ua.ac.be (A.-M. Lambeir). 0006-2952/$ – see front matter # 2005 Elsevier Inc. All rights reserved. doi:10.1016/j.bcp.2005.04.009