A method for identifying a compound that inhibits meprin activity, comprising: (a) providing a reaction mixture comprising a meprin and an auxiliary enzyme; (b) adding a test compound; (c) incubating the reaction mixture of step (b); (d) adding a labeled substrate to the reaction mixture; (e) incubating the reaction mixture of step (d); (f) optionally terminating the reaction; (g) measuring the amount of free label in the reaction mixture; and (h) determining if the test compound inhibits meprin activity by comparing the amount of free label from the reaction mixture with the amount of free label from a control reaction mixture to which no test compound was added, wherein a reduced amount of free label in the reaction mixture compared to the amount of free label in the control reaction mixture is indicative of inhibition of the enzymatic catalytic activity of a meprin by the test compound; wherein said labeled substrate is a labeled oligopeptide of formula (I), X 1 X 2 X 3 X 4 X 5 X 6 X 7 X 8 X 9 X 10 X 11 P-label (I) wherein X 1 may be a peptide or any amino acid including proteinogenic amino acids, non-proteinogenic amino acids, L-amino acids and D-amino acids; X 2 , X 3 , X 4 , X 5 , X 6 , X 7 , X 8 and X 9 may be any amino acid including proteinogenic amino acids, non-proteinogenic amino acids, L-amino acids and D-amino acids; and at least one of X 1 , X 2 , X 3 , X 4 , X 5 , X 6 , X 7 , X 8 and X 9 is present and the others may be absent; and the label is selected AMC and pNA; or a labeled oligopeptide of formula (II) X 4 X 5 X 6 X 7 X 8 X 9 X 10 X 11 P-label (II) wherein X 4 is any amino acid or a peptide; X 5 is any amino acid; X 6 is any amino acid; X 7 is amino acid selected from the group consisting of A, D, E, I, L, P, S, T, V, and Y; X 8 is amino acid selected from the group consisting of A, D, E, I, L, P, Q, S, T, Q, and V; X 9 is amino acid selected from the group consisting of A, D, E, L, N, Q, S; X 10 is amino acid selected from the group consisting of D, E and T; X 11 is amino acid selected from the group consisting of A, I, L, V, and F; and the label is pNA or AMC; or a labeled oligopeptide of formula (III) KKGYVADAP-label (III), wherein the label is selected from AMC and pNA. (a) providing a reaction mixture comprising a meprin and an auxiliary enzyme; (b) adding a test compound; (c) incubating the reaction mixture of step (b); (d) adding a labeled substrate to the reaction mixture; (e) incubating the reaction mixture of step (d); (f) optionally terminating the reaction; (g) measuring the amount of free label in the reaction mixture; and (h) determining if the test compound inhibits meprin activity by comparing the amount of free label from the reaction mixture with the amount of free label from a control reaction mixture to which no test compound was added, wherein a reduced amount of free label in the reaction mixture compared to the amount of free label in the control reaction mixture is indicative of inhibition of the enzymatic catalytic activity of a meprin by the test compound; X 4 is any amino acid or a peptide; X 5 is any amino acid; X 6 is any amino acid; X 7 is amino acid selected from the group consisting of A, D, E, I, L, P, S, T, V, and Y; X 8 is amino acid selected from the group consisting of A, D, E, I, L, P, Q, S, T, Q, and V; X 9 is amino acid selected from the group consisting of A, D, E, L, N, Q, S; X 10 is amino acid selected from the group consisting of D, E and T; X 11 is amino acid selected from the group consisting of A, I, L, V, and F; and <EOS>