Proline-specific endoprotease and use thereof

An isolated or purified polypeptide having proline-specific endoprotease activity, wherein the polypeptide after being at a temperature of 65° C. for 15 minutes has less than 70% residual activity as a substrate on acetyl-AlaAlaPro-paranitroaniline (Ac-AAP-pNA), wherein the polypeptide is selected from the group consisting of:

• i. a polypeptide, which, when aligned with the amino acid sequence of SEQ ID NO:
• 1 comprises an amino acid substitution at a position corresponding to position 469, and optionally at least one further amino acid substitution at position 204, 304, 377, 466, and/or 477, wherein the position corresponds to SEQ ID NO:1;
• ii. a polypeptide, which, when aligned with the amino acid sequence of SEQ ID NO:1 comprises an amino acid selected from the group consisting of Ala (A), Cys (C), Asp (D), Glu (E), Phe (F), Gly (G), His (H), Ile (I), Lys (K), Leu (L), Met (M), Asn (N), Gln (Q), Arg (R), Ser (S), Thr (T), Val (V), Trp (W), and Tyr (Y) at a position corresponding to position 469, and optionally an amino acid of Phe (F) at position 204, Ser (S) at position 304, Ala (A) at position 377, Thr (T) at position 466 and/or Ala (A) at position 477, and wherein the position corresponds to SEQ ID NO:1;
• iii. a polypeptide comprising the amino acid sequence of SEQ ID NO:1, wherein SEQ ID NO:1 comprises at least one amino acid substitution selected from the group consisting of P469A, P469C, P469D, P469E, P469F, P469G, P469H, P469I, P469K, P469L, P469M, P469N, P469Q, P469R, P469S, P469T, P469V, P469W, and P469Y, and optionally an amino acid substitution I204F, P304S, P377A, P466T, and/or P477A, and wherein the amino acid substitution corresponds to SEQ ID NO:1;
• iv. the polypeptide of i), ii), or iii), but lacking a signal sequence and/or a proprotein sequence;
• v. the polypeptide of i), ii), iii), or iv), wherein the polypeptide has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to the amino acid sequence of SEQ ID NO:1;
• and,
• vi. a polypeptide encoded by a nucleic acid which has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO:2, or to a mature coding sequence of SEQ ID NO:2, wherein SEQ ID NO:2 comprises at least one mutation encoding at least an amino acid substitution selected from the group P469A, P469C, P469D, P469E, P469F, P469G, P469H, P469I, P469K, P469L, P469M, P469N, P469Q, P469R, P469S, P469T, P469V, P469W, and P469Y, and optionally wherein SEQ ID NO:2 comprises at least one additional mutation encoding an amino acid substitution I204F, P304S, P377A, P466T, and/or P477A, and wherein the amino acid substitutions correspond to SEQ ID NO:1.