Potent and specific immunoproteasome inhibitors

• US 20060241056A1
• Filed: 03/13/2006
• Published: 10/26/2006
• Est. Priority Date: 03/11/2005
• Status: Active Grant

• Current Assignee: Mount Sinai School of Medicine (Sinai Health System), University of North Carolina At Chapel Hill (University of North Carolina System)
• Original Assignee: Mount Sinai School of Medicine (Sinai Health System), University of North Carolina At Chapel Hill (University of North Carolina System)
• Inventors: Orlowski, Robert Z., Orlowski, Marian
• Granted Patent: US 7,589,066 B2
• Time in Patent Office: Days
• US Class Current: 514/1.900
• CPC Class Codes: A61K 38/00 Medicinal preparations containing peptides peptides containing beta-lactam rings A61K31/00; cyclic dipeptides not having in their molecule any other peptide link than those which form their ring, e.g. piperazine-2,5-diones, A61K31/00; ergot alkaloids of the cyclic peptide type A61K31/48; containing macromolecular compounds having statistically distributed amino acid units A61K31/74; medicinal preparations containing antigens or antibodies A61K39/00; medicinal preparations characterised by the non-active ingredients, e.g. peptides as drug carriers, A61K47/00
• CPC Class Codes: C07K 5/06078 and aromatic or cycloaliphatic
• CPC Class Codes: C07K 5/06191 containing heteroatoms different from O, S, or N
• CPC Class Codes: C07K 5/0812 and aromatic or cycloaliphatic
• CPC Class Codes: C07K 5/0827 containing heteroatoms different from O, S, or N
• CPC Class Codes: C07K 5/1016 and aromatic or cycloaliphatic
• CPC Class Codes: C07K 5/1027 containing heteroatoms different from O, S, or N

Abstract

Compounds and methods of selectively inhibiting an immunoproteasome are described. Also described are methods of treating a cancer, an inflammation, and/or an autoimmune disease and methods of suppressing endogenous antigenic peptide generation by administering to a subject in need of treatment thereof a therapeutic amount of an immunoproteasome specific inhibitor.

Claims

1. A compound having a 10-fold or greater preference for inhibiting an immunoproteasome as compared to a constitutive proteasome, said compound having a structure of Formula (I):

2. The compound of claim 1, wherein A₁, A₂, and A₃ each comprise amide bonds and the compound of Formula (I) is a compound of Formula (II):

3. The compound of claim 2, wherein R₁ is selected from the group consisting of alkyl, branched alkyl, and aralkyl.

4. The compound of claim 3, wherein R₁ is benzyl or n-butyl.

5. The compound of claim 2, wherein D is selected from the group consisting of:

6. The compound of claim 2, wherein W is

7. The compound of claim 4, wherein:

p is 0;

q is 0;

R₁ is benzyl; and

R₄ is selected from the group consisting of benzyl, isobutyl, methyl, and phenylethyl.

8. The compound of claim 4, wherein:

p is 1;

q is 1;

R₂ is methyl or benzyl;

R₃ and Q₃ together are C₃ alkylene; and

R₄ is H.

9. The compound of claim 4, wherein:

p is 0;

q is 1;

R₂ is isobutyl or benzyl; and

R₄ is isobutyl or H.

10. The compound of claim 4, wherein the compound is selected from the group consisting of:

N-carbobenzyloxy-phenylalanyl-phenylalanylal,

N-carbobenzyloxy-homophenylalanyl-phenylalanylal,

N-carbobenzyloxy-leucyl-phenylalanylal,

N-carbobenzyloxy-alanyl-phenylalanylal,

N-carbobenzyloxy-glycyl-prolyl-alanyl-phenylalanylal,

N-carbobenzyloxy-glycyl-prolyl-phenylalanyl-phenylalanylal,

N-carbobenzyloxy-glycyl-phenylalanyl-phenylalanylal,

N-carbobenzyloxy-leucyl-norleucine boronic acid,

N-carbobenzyloxy-phenylalanyl-phenylalanine boronic acid,

N-carbobenzyloxy-homophenylalanyl-phenylalanine boronic acid,

N-carbobenzyloxy-leucyl-phenylalanine boronic acid,

N-carbobenzyloxy-glycyl-prolyl-alanyl-phenylalanine boronic acid,

N-carbobenzyloxy-glycyl-prolyl-phenylalanyl-phenylalanine boronic acid,

N-carbobenzyloxy-leucyl-leucyl-phenylalanine boronic acid,

N-carbobenzyloxy-glycyl-phenylalanyl-phenylalanine boronic acid,

N-carbobenzyloxy-leucyl-norleucine methyl vinyl sulfone,

N-carbobenzyloxy-phenylalanyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-homophenylalanyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-leucyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-alanyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-glycyl-prolyl-alanyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-glycyl-prolyl-phenylalanyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-leucyl-leucyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-glycyl-phenylalanyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-leucyl-norleucine epoxy ketone,

N-carbobenzyloxy-phenylalanyl-phenylalanine epoxy ketone,

N-carbobenzyloxy-homophenylalanyl-phenylalanine epoxy ketone,

N-carbobenzyloxy-leucyl-phenylalanine epoxy ketone,

N-carbobenzyloxy-alanyl-phenylalanine epoxy ketone,

N-carbobenzyloxy-glycyl-prolyl-alanyl-phenylalanine epoxy ketone,

N-carbobenzyloxy-glycyl-prolyl-phenylalanyl-phenylalanine epoxy ketone,

N-carbobenzyloxy-leucyl-leucyl-phenylalanine epoxy ketone, and

N-carbobenzyloxy-glycyl-phenylalanyl-phenylalanine epoxy ketone.

11. A method of selectively inhibiting an immunoproteasome in a cell where such inhibition is desirable, the method comprising contacting the cell with a proteasome inhibitor having specificity for an immunoproteasome.

12. The method of claim 11, wherein the proteasome inhibitor has a 10-fold or greater preference for inhibiting the immunoproteasome as compared to a constitutive proteasome and comprises a compound of Formula (I):

13. The method of claim 12, wherein A₁, A₂, and A₃ each comprise amide bonds and the compound of Formula (I) is a compound of Formula (II):

14. The method of claim 13, wherein R₁ is selected from the group consisting of alkyl, branched alkyl, and aralkyl.

15. The method of claim 14, wherein R₁ is benzyl or n-butyl.

16. The method of claim 13, wherein D is selected from the group consisting of:

17. The method of claim 13, wherein W is

18. The method of claim 15, wherein:

p is 0;

q is 0; and

R₄ is selected from the group consisting of benzyl, isobutyl, methyl, and phenylethyl.

19. The method of claim 15, wherein:

p is 1;

q is 1;

R₂ is methyl or benzyl;

R₃ and Q₃ together are C₃ alkylene; and

R₄ is H.

20. The method of claim 15, wherein:

p is 0;

q is 1;

R₂ is isobutyl or benzyl; and

R₄ is isobutyl or H.

21. The method of claim 15, wherein the proteasome inhibitor is selected from the group consisting of:

N-carbobenzyloxy-leucyl-norleucinal,

N-carbobenzyloxy-phenylalanyl-phenylalanylal,

N-carbobenzyloxy-homophenylalanyl-phenylalanylal,

N-carbobenzyloxy-leucyl-phenylalanylal,

N-carbobenzyloxy-alanyl-phenylalanylal,

N-carbobenzyloxy-glycyl-prolyl-alanyl-phenylalanylal,

N-carbobenzyloxy-glycyl-prolyl-phenylalanyl-phenylalanylal,

N-carbobenzyloxy-leucyl-leucyl-phenylalanylal,

N-carbobenzyloxy-glycyl-phenylalanyl-phenylalanylal,

N-carbobenzyloxy-leucyl-norleucine boronic acid,

N-carbobenzyloxy-phenylalanyl-phenylalanine boronic acid,

N-carbobenzyloxy-homophenylalanyl-phenylalanine boronic acid,

N-carbobenzyloxy-leucyl-phenylalanine boronic acid,

N-carbobenzyloxy-alanyl-phenylalanine boronic acid,

N-carbobenzyloxy-glycyl-prolyl-alanyl-phenylalanine boronic acid,

N-carbobenzyloxy-glycyl-prolyl-phenylalanyl-phenylalanine boronic acid,

N-carbobenzyloxy-leucyl-leucyl-phenylalanine boronic acid,

N-carbobenzyloxy-glycyl-phenylalanyl-phenylalanine boronic acid,

N-carbobenzyloxy-leucyl-norleucine methyl vinyl sulfone,

N-carbobenzyloxy-phenylalanyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-homophenylalanyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-leucyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-alanyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-glycyl-prolyl-alanyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-glycyl-prolyl-phenylalanyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-leucyl-leucyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-glycyl-phenylalanyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-leucyl-norleucine epoxy ketone,

N-carbobenzyloxy-phenylalanyl-phenylalanine epoxy ketone,

N-carbobenzyloxy-homophenylalanyl-phenylalanine epoxy ketone,

N-carbobenzyloxy-leucyl-phenylalanine epoxy ketone,

N-carbobenzyloxy-alanyl-phenylalanine epoxy ketone,

N-carbobenzyloxy-glycyl-prolyl-alanyl-phenylalanine epoxy ketone,

N-carbobenzyloxy-glycyl-prolyl-phenylalanyl-phenylalanine epoxy ketone,

N-carbobenzyloxy-leucyl-leucyl-phenylalanine epoxy ketone, and

N-carbobenzyloxy-glycyl-phenylalanyl-phenylalanine epoxy ketone.

22. The method of claim 11, wherein the cell is in a subject.

23. The method of claim 11, wherein the proteasome inhibitor has a K_i of 25 μ

M or less for the immunoproteasome.

24. The method of claim 11, wherein the proteasome inhibitor has a greater than a 100-fold preference for inhibiting the immunoproteasome as compared to the constitutive proteasome.

25. A method for treating a cancer in a subject in need of treatment thereof, the method comprising administering to the subject a therapeutic amount of a proteasome inhibitor having specificity for an immunoproteasome.

26. The method of claim 25, wherein the proteasome inhibitor has a 10-fold or greater preference for inhibiting the immunoproteasome as compared to a constitutive proteasome and comprises a compound of Formula (I):

27. The method of claim 26, wherein A₁, A₂, and A₃ each comprise amide groups and the compound of Formula (I) is a compound of Formula (II):

28. The method of claim 27, wherein R₁ is selected from the group consisting of alkyl, branched alkyl, and aralkyl.

29. The method of claim 28, wherein R₁ is benzyl or n-butyl.

30. The method of claim 27, wherein D is selected from the group consisting of:

31. The method of claim 27, wherein W is

32. The method of claim 29, wherein:

p is 0;

q is 0; and

R₄ is selected from the group consisting of benzyl, isobutyl, methyl and phenylethyl.

33. The method of claim 29, wherein:

p is 1;

q is 1;

R₂ is methyl or benzyl;

R₃ and Q₃ together are C₃ alkylene; and

R₄ is H.

34. The method of claim 29, wherein:

p is 0;

q is 1;

R₂ is isobutyl or benzyl; and

R₄ is isobutyl or H.

35. The method of claim 29, wherein the proteasome inhibitor is selected from the group consisting of:

N-carbobenzyloxy-leucyl-norleucinal,

N-carbobenzyloxy-phenylalanyl-phenylalanylal,

N-carbobenzyloxy-homophenylalanyl-phenylalanylal,

N-carbobenzyloxy-leucyl-phenylalanylal,

N-carbobenzyloxy-alanyl-phenylalanylal,

N-carbobenzyloxy-glycyl-prolyl-alanyl-phenylalanylal,

N-carbobenzyloxy-glycyl-prolyl-phenylalanyl-phenylalanylal,

N-carbobenzyloxy-leucyl-leucyl-phenylalanylal,

N-carbobenzyloxy-glycyl-phenylalanyl-phenylalanylal,

N-carbobenzyloxy-leucyl-norleucine boronic acid,

N-carbobenzyloxy-phenylalanyl-phenylalanine boronic acid,

N-carbobenzyloxy-homophenylalanyl-phenylalanine boronic acid,

N-carbobenzyloxy-leucyl-phenylalanine boronic acid,

N-carbobenzyloxy-alanyl-phenylalanine boronic acid,

N-carbobenzyloxy-glycyl-prolyl-alanyl-phenylalanine boronic acid,

N-carbobenzyloxy-glycyl-prolyl-phenylalanyl-phenylalanine boronic acid,

N-carbobenzyloxy-leucyl-leucyl-phenylalanine boronic acid,

N-carbobenzyloxy-glycyl-phenylalanyl-phenylalanine boronic acid,

N-carbobenzyloxy-leucyl-norleucine methyl vinyl sulfone,

N-carbobenzyloxy-phenylalanyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-homophenylalanyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-leucyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-alanyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-glycyl-prolyl-alanyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-glycyl-prolyl-phenylalanyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-leucyl-leucyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-glycyl-phenylalanyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-leucyl-norleucine epoxy ketone,

N-carbobenzyloxy-phenylalanyl-phenylalanine epoxy ketone,

N-carbobenzyloxy-homophenylalanyl-phenylalanine epoxy ketone,

N-carbobenzyloxy-leucyl-phenylalanine epoxy ketone,

N-carbobenzyloxy-alanyl-phenylalanine epoxy ketone,

N-carbobenzyloxy-glycyl-prolyl-alanyl-phenylalanine epoxy ketone,

N-carbobenzyloxy-glycyl-prolyl-phenylalanyl-phenylalanine epoxy ketone,

N-carbobenzyloxy-leucyl-leucyl-phenylalanine epoxy ketone, and

N-carbobenzyloxy-glycyl-phenylalanyl-phenylalanine epoxy ketone.

36. The method of claim 25, wherein the proteasome inhibitor has a K_i of 25 μ

M or less for the immunoproteasome.

37. The method of claim 25, wherein the proteasome inhibitor has a greater than a 100-fold preference for inhibiting the immunoproteasome as compared to the constitutive proteasome.

38. The method of claim 25, wherein the cancer is selected from the group consisting of multiple myeloma, Hodgkin'"'"'s lymphoma, non-Hodgkin'"'"'s lymphoma, acute leukemia, and chronic leukemia.

39. The method of claim 25, wherein the subject is a human.

40. The method of claim 25, wherein the method comprises administering to the subject a therapeutic amount of a proteasome inhibitor having specificity for the immunoproteasome and one or more additional anti-cancer therapeutic agents.

41. A method for treating inflammation in a subject in need of treatment thereof, the method comprising administering to the subject a therapeutic amount of a proteasome inhibitor having specificity for an immunoproteasome.

42. The method of claim 41, wherein the proteasome inhibitor has a 10-fold or greater preference for inhibiting the immunoproteasome as compared to a constitutive proteasome and comprises a compound of Formula (I):

43. The method of claim 42, wherein A₁, A₂, and A₃ each comprise an amide group and the compound of Formula (I) is a compound of Formula (II):

44. The method of claim 43, wherein R₁ is selected from the group consisting of alkyl, branched alkyl, and aralkyl.

45. The method of claim 44, wherein R₁ is benzyl or n-butyl.

46. The method of claim 43, wherein D is selected from the group consisting of:

47. The method of claim 43, wherein W is

48. The method of claim 45, wherein:

p is 0;

q is 0; and

R₄ is selected from the group consisting of benzyl, isobutyl, methyl, and phenylethyl.

49. The method of claim 45, wherein:

p is 1;

q is 1;

R₂ is methyl or benzyl;

R₃ and Q₃ together are C₃ alkylene; and

R₄ is H.

50. The method of claim 45, wherein:

p is 0;

q is 1;

R₂ is isobutyl or benzyl; and

R₄ is isobutyl or H.

51. The method of claim 45, wherein the proteasome inhibitor is selected from the group consisting of:

N-carbobenzyloxy-leucyl-norleucinal,

N-carbobenzyloxy-phenylalanyl-phenylalanylal,

N-carbobenzyloxy-homophenylalanyl-phenylalanylal,

N-carbobenzyloxy-leucyl-phenylalanylal,

N-carbobenzyloxy-alanyl-phenylalanylal,

N-carbobenzyloxy-glycyl-prolyl-alanyl-phenylalanylal,

N-carbobenzyloxy-glycyl-prolyl-phenylalanyl-phenylalanylal,

N-carbobenzyloxy-leucyl-leucyl-phenylalanylal,

N-carbobenzyloxy-glycyl-phenylalanyl-phenylalanylal,

N-carbobenzyloxy-leucyl-norleucine boronic acid,

N-carbobenzyloxy-phenylalanyl-phenylalanine boronic acid,

N-carbobenzyloxy-homophenylalanyl-phenylalanine boronic acid,

N-carbobenzyloxy-leucyl-phenylalanine boronic acid,

N-carbobenzyloxy-alanyl-phenylalanine boronic acid,

N-carbobenzyloxy-glycyl-prolyl-alanyl-phenylalanine boronic acid,

N-carbobenzyloxy-glycyl-prolyl-phenylalanyl-phenylalanine boronic acid,

N-carbobenzyloxy-leucyl-leucyl-phenylalanine boronic acid,

N-carbobenzyloxy-glycyl-phenylalanyl-phenylalanine boronic acid,

N-carbobenzyloxy-leucyl-norleucine methyl vinyl sulfone,

N-carbobenzyloxy-phenylalanyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-homophenylalanyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-leucyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-alanyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-glycyl-prolyl-alanyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-glycyl-prolyl-phenylalanyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-leucyl-leucyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-glycyl-phenylalanyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-leucyl-norleucine epoxy ketone,

N-carbobenzyloxy-phenylalanyl-phenylalanine epoxy ketone,

N-carbobenzyloxy-homophenylalanyl-phenylalanine epoxy ketone,

N-carbobenzyloxy-leucyl-phenylalanine epoxy ketone,

N-carbobenzyloxy-alanyl-phenylalanine epoxy ketone,

N-carbobenzyloxy-glycyl-prolyl-alanyl-phenylalanine epoxy ketone,

N-carbobenzyloxy-glycyl-prolyl-phenylalanyl-phenylalanine epoxy ketone,

N-carbobenzyloxy-leucyl-leucyl-phenylalanine epoxy ketone, and

N-carbobenzyloxy-glycyl-phenylalanyl-phenylalanine epoxy ketone.

52. The method of claim 41, wherein the proteasome inhibitor has a K_i of 25 μ

M or less for the immunoproteasome.

53. The method of claim 41, wherein the proteasome inhibitor has a greater than a 100-fold preference for inhibiting the immunoproteasome as compared to the constitutive proteasome.

54. The method of claim 41, wherein the subject is a human.

55. The method of claim 41, wherein the inflammation is related to one of the group consisting of transplantation rejection, arthritis, rheumatoid arthritis, infection, dermatosis, inflammatory bowel disease, asthma, osteoporosis, osteoarthritis, psoriasis, and restenosis.

56. A method for treating an auto-immune disease in a subject in need of treatment thereof, the method comprising administering to the subject a therapeutic amount of a proteasome inhibitor having specificity for an immunoproteasome.

57. The method of claim 56, wherein the proteasome inhibitor has a 10-fold or greater preference for inhibiting the immunoproteasome as compared to a constitutive proteasome and comprises a compound of Formula (I):

58. The method of claim 57, wherein A₁, A₂, and A₃ each comprise an amide group and the compound of Formula (I) is a compound of Formula (II):

59. The method of claim 58, wherein R₁ is selected from the group consisting of alkyl, branched alkyl, and aralkyl.

60. The method of claim 59, wherein R₁ is benzyl or n-butyl.

61. The method of claim 58, wherein D is selected from the group consisting of:

62. The method of claim 58, wherein W is

63. The method of claim 60, wherein:

p is 0;

q is 0; and

R₄ is selected from the group consisting of benzyl, isobutyl, methyl and phenylethyl.

64. The method of claim 60, wherein:

p is 1;

q is 1;

R₂ is methyl or benzyl;

R₃ and Q₃ together are C₃ alkylene; and

R₄ is H.

65. The method of claim 60, wherein:

p is 0;

q is 1;

R₂ is isobutyl or benzyl; and

R₄ is isobutyl or H.

66. The method of claim 60, wherein the proteasome inhibitor is selected from the group consisting of:

N-carbobenzyloxy-leucyl-norleucinal,

N-carbobenzyloxy-phenylalanyl-phenylalanylal,

N-carbobenzyloxy-homophenylalanyl-phenylalanylal,

N-carbobenzyloxy-leucyl-phenylalanylal,

N-carbobenzyloxy-alanyl-phenylalanylal,

N-carbobenzyloxy-glycyl-prolyl-alanyl-phenylalanylal,

N-carbobenzyloxy-glycyl-prolyl-phenylalanyl-phenylalanylal,

N-carbobenzyloxy-leucyl-leucyl-phenylalanylal,

N-carbobenzyloxy-glycyl-phenylalanyl-phenylalanylal,

N-carbobenzyloxy-leucyl-norleucine boronic acid,

N-carbobenzyloxy-phenylalanyl-phenylalanine boronic acid,

N-carbobenzyloxy-homophenylalanyl-phenylalanine boronic acid,

N-carbobenzyloxy-leucyl-phenylalanine boronic acid,

N-carbobenzyloxy-alanyl-phenylalanine boronic acid,

N-carbobenzyloxy-glycyl-prolyl-alanyl-phenylalanine boronic acid,

N-carbobenzyloxy-glycyl-prolyl-phenylalanyl-phenylalanine boronic acid,

N-carbobenzyloxy-leucyl-leucyl-phenylalanine boronic acid,

N-carbobenzyloxy-glycyl-phenylalanyl-phenylalanine boronic acid,

N-carbobenzyloxy-leucyl-norleucine methyl vinyl sulfone,

N-carbobenzyloxy-phenylalanyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-homophenylalanyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-leucyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-alanyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-glycyl-prolyl-alanyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-glycyl-prolyl-phenylalanyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-leucyl-leucyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-glycyl-phenylalanyl-phenylalanine methyl vinyl sulfone,

N-carbobenzyloxy-leucyl-norleucine epoxy ketone,

N-carbobenzyloxy-phenylalanyl-phenylalanine epoxy ketone,

N-carbobenzyloxy-homophenylalanyl-phenylalanine epoxy ketone,

N-carbobenzyloxy-leucyl-phenylalanine epoxy ketone,

N-carbobenzyloxy-alanyl-phenylalanine epoxy ketone,

N-carbobenzyloxy-glycyl-prolyl-alanyl-phenylalanine epoxy ketone,

N-carbobenzyloxy-glycyl-prolyl-phenylalanyl-phenylalanine epoxy ketone,

N-carbobenzyloxy-leucyl-leucyl-phenylalanine epoxy ketone, and

N-carbobenzyloxy-glycyl-phenylalanyl-phenylalanine epoxy ketone.

67. The method of claim 56, wherein the proteasome inhibitor has a K_i of 25 μ

M or less for the immunoproteasome.

68. The method of claim 56, wherein the proteasome inhibitor has a greater than a 100-fold preference for inhibiting the immunoproteasome as compared to the constitutive proteasome.

69. The method of claim 56, wherein the autoimmune disease is selected from the group consisting of rheumatoid arthritis, multiple sclerosis, systemic lupus erythromatosis (SLE), scleroderma, diabetes, inflammatory bowel disease, psoriasis, atherosclerosis, graft versus host disease, and tissue transplant rejection.

70. A method of suppressing endogenous antigenic peptide generation in a subject in need thereof, the method comprising administering to the subject a therapeutic amount of a proteasome inhibitor having specificity for an immunoproteasome.

71. A pharmaceutical formulation comprising:

(a) a compound having a 10-fold or greater preference for inhibiting an immunoproteasome as compared to a constitutive proteasome; and

(b) a pharmaceutically acceptable carrier.