Compounds, pharmaceuticals, kits and methods are provided for use with DPP-IV and other S9 proteases that comprise a compound comprising: wherein M is N or CR.sub.4; Q.sup.1 and Q.sup.2 are each independently selected from the group consisting of CO, SO, SO.sub.2, and C.dbd.NR.sub.9; and each L, X, R.sub.1, R.sub.2, and R.sub.3 are as defined herein.