Patent ID: 8313920

Claim:
A method of screening compounds to identify compounds which modulate dipeptidyl peptidase I (DPPI) activities, comprising the steps of: a. adding a substrate peptide of DPPI to a reaction mixture which comprises DPPI and a compound to be tested, wherein said substrate of DPPI is selected from the group consisting of: (i) an isolated peptide of SEQ ID NO: 1; (ii) an isolated peptide of SEQ ID NO: 2; (iii) an isolated peptide of SEQ ID NO: 3; (iv) an isolated peptide of SEQ ID NO: 4; (v) an isolated peptide of SEQ ID NO: 5; (vi) an isolated peptide of SEQ ID NO: 6; (vii) an isolated peptide of SEQ ID NO: 7; and (viii) an isolated peptide of up to 100 amino acids comprising SEQ ID NO:1, SEQ ID NO:2 or SEQ ID NO: 7; b. measuring the molecular weight of said substrate and/or mass ratio of said substrate peptide and corresponding product peptide; c. comparing the results of step (b) to the results of a positive control containing no test compound; d. determining whether the molecular weight and/or mass ratio differs from the control; and e. selecting a compound for which the results differ from the control.