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Proteasome Subunit Nomenclature Guide

Proteasome subunit nomenclature can be a bewildering array of 'standard','alternative' and 'miscellaneous naming conventions. Our useful table summarises the various designations of Baumeister, Finley and Dubiel and references each subunit to its primary accession number. Need more information? If you have any questions relating to proteasome subunit nomenclature, a member of our technical support team will be happy to assist.


Accession no.*
Length (a.a.)
MW (Da)

20S Proteasome


α-type subunits

α1 iota α6 PSMA6 Pros27, p27k, C7, Prs2, Y8, Prc2, Scl1 P60900 246 27399
α2 C3 α2 PSMA2 Hc3, Psc3, Pre8, Prs4, Y7, Lmpc3 P25787 233 25767
α3 C9 α4  PSMA4  Hc9, Psc9, Pre9, Prs5, Y13  P25789  261 29484
α4 C6 α7  PSMA7  RC6-1, XAPC7, Hspc, Pre6 O14818 248 27887
α5  zeta  α5  PSMA5 Pup2, Doa5 P28066 241 26411
α6 C2  α1  PSMA1  Hc2, Nu, Pros30, Psc2, Pre5  P25786 263 29556
α7  C8  α3  PSMA3  Hc8, Psc8, Pre10, Prs1, C1, Prc1  P25788  254 28302

β-type subunits

β1  β6 PSMB6 delta, Lmpy, Pre3, Lmp19 P28072 239/205** 25358/21904**
β1i Lmp2 β9 PSMB9 Psmb6i, Ring12 P28065 219/199** 23264/21276**
β2 Z β7 PSMB7 alpha, Pup1, Mmc14 Q99436 277/234** 29965/25295**
β2i MECL-1 β10 PSMB10 Lmp10 P40306 273/234** 28936/24648**
β3 C10 β3 PSMB3 theta, Pup3, C10-II P49720 205 22818
β4 C7 β2 PSMB2 Pre1, C11, C7-I P49721 201 22836
β5 X β5 PSMB5 epsilon, LmpX, MB1, Pre2, Doa3, Prg1 P28074 263/204** 28480/22458**
β5i Lmp7 β8 PSMB8 Psmb5i, Ring10, Y2, C13, Mc13 P28062 276/204** 30354/22660**
β5t  - β11 PSMB11 beta5i-like A5LHX3 300/251** 32530/27232**
β6 C5 β1 PSMB1 gamma, Psc5, Pre7, Prs3, Pts1 P20618 241 26489
β7 N3 β4 PSMB4 beta, Pros26, HsN3, Pre4, Rn3, Lmp3 P28070 264/219** 29204/24392**

19S Proteasome (PA700) Regulator


ATPase subunits

Rpt1 S7 Subunit 7 PSMC2 Mss1, Yta3, Cim5 P35998 432 48503
Rpt2 S4 Subunit 4 PSMC1 Yhs4, Yta5, P26s4 P62191 440 49185
Rpt3 S6b Subunit 6b PSMC4 S6, Mip224, Tbp7, Yta2, Ynt1, Cip21 P43686 418 47336
Rpt4 S10b Subunit 10b PSMC6 p42, Sug2, Prs10, Pcs1, Crl13 P62333 389 44173
Rpt5 S6a Subunit 6a PSMC3 S6’, p50, Tbp1, Yta1, Sata P17980 439 49204
Rpt6 S8 Subunit 8 PSMC5 p45, Trip1, Sug1, Cim3, Crl3, Tbpy, Tby1 P62195 406 45626

Non-ATPase subunits

Rpn1 S2 Subunit 2 PSMD2 p97, Trap2, Hrd2, Nas1, Rpd1 Q13200 908 100200
Rpn2 S1 Subunit 1 PSMD1 p112, Sen3 Q99460 953 105836
Rpn3 S3 Subunit 3 PSMD3 p58, Sun2, P91a, Tstap91a O43242 534 60978
Rpn4  -  - RPN4 (S.c.) Son1, Ufd5 Q03465 (S.c.) 531 60153
Rpn5  - Subunit 12 PSMD12 p55, Nas5 O00232 455 52773
Rpn6 S9 Subunit 11 PSMD11 p44.5, Nas4 O00231 421 47333
Rpn7 S10a Subunit 6 PSMD6 SGA-113M, p44S10, p42A, PFAAP4 Q15008 389 45531
Rpn8 S12 Subunit 7 PSMD7 p40, Mov34L P51665 324 37025
Rpn9 S11 Subunt 13 PSMD13 p40.5, Les1, Nas7 Q9UNM6 376 42945
Rpn10 S5a Subunit 4 PSMD4 ASF1, Mcb1, Sun1 P55036 377 40737
Rpn11 S13 Subunit 14 PSMD14 Poh1, Mpr1, Mad1, Pad1 O00487 310 34577
Rpn12 S14  Subunit 8 PSMD8 p31, Nin1 P48556 350 39612
Rpn13     RPN13 (S.c.) DAQ1 O13563 (S.c.)  156 17902
 - S5b Subunit 5 PSMD5   Q16401 503 56065
 - S15 Subunit 9 PSMD9 p27 O00233 223 24682
Gankyrin  - Subunit 10 PSMD10 p28, p28(GANK) O75832 226 24428

11S (PA28) Proteasome Activator

11Sα PA28α  Subunit 1  PSME1  REGα, IFI5111 Q06323 249 28723
11Sβ  PA28β  Subunit 2  PSME 2  REGβ Q9UL46  238 27270
11Sγ  PA28γ  Subunit 3  PSME 3  REGγ, Ki antigen P61289 253 29375

PA200 Proteasome Activator

PA200 Subunit 4 PSME4     Q14997  1843  211334



*Human gene/accession number. **Pro/mature form.


1. W. Baumeister et al. The proteasome: paradigm of a self-compartmentalizing protease. Cell 1998 92 367
2. D. Finley et al. Unified nomenclature for subunits of the Saccharomyces cerevisiae proteasome regulatory particle. Trends Biochem. Sci. 1998 23 244
3. W. Dubiel et al. Subunits of the regulatory complex of the 26S protease. Mol. Biol. Reports 1995 21 27
4. W. Dubiel et al. Purification of an 11S regulator of the multicatalytic protease. J. Biol. Chem. 1992 267 22369
5. C.P. Ma et al. Identification, purification, and characterization of a protein activator (PA28) of the 20S proteasome (macropain). J. Biol. Chem. 1992 267 10515


Other proteasome resources

Easy-to-use kits for measurement of 20S proteasome activity 

3 Item(s)

Set Descending Direction
  1. VIVAdetect™ proteasome activity kit (lysate)

    Flexible, robust, easy-to-use kit for measurement of proteasome activity in biological samples

    Learn More

  2. VIVAdetect™ 20S proteasome assay kit

    Flexible, robust, easy-to-use kit for measurement of purified 20S proteasome activity

    Learn More

  3. VIVAdetect™ 20S proteasome assay kit PLUS

    Flexible, robust, easy-to-use kit for measurement of all three activities of purified 20S proteasomes

    Learn More

3 Item(s)

Set Descending Direction