Proteins isolated from Coprinus clastophyllus having prolyl oligopeptidase activity, nucleic acids encoding the protein and methods for producing and using the protein, wherein SEQ ID NO:5, SEQ ID NO:6, SEQ ID NO:9 and SEQ ID NO:10 must be contained therein to at least 60% similarity. The proteins and nucleic acids have improved heat stability and perform more favorably in vivo having optimum activity conditions around 40 degrees centigrade and around pH 7, and can therefore be used in medicaments for the treatment of celiac disease caused by proline abundant gluten or other applications.