Concurrently other DPP - 4 inhibitors without a nitrile group were published .
Inhibitors contained other serine - interacting motifs , e.g. boronic acids , phosphonates or diacyl hydroxylamines .
Concurrently other DPP - 4 inhibitors without a nitrile group were published but they contained other serine - interacting motifs , e.g. boronic acids , phosphonates or diacyl hydroxylamines .