Seroatlas · Human Serome Atlas

CPB2

Carboxypeptidase B2

Also known as: CBPB2_HUMAN, CPU, PCPB, TAFI

Cross-references: UniProt · Ensembl · Human Protein Atlas · GeneCards · NCBI Gene

Protein identityUniProt · HPA

UniProt accession
Q96IY4
Gene
CPB2
Ensembl
ENSG00000080618
Chromosome
13
Canonical length
423 aa
Protein class
Enzymes, FDA approved drug targets, Plasma proteins, Predicted secreted proteins
Secretome location
Secreted to blood

OverviewNCBI Gene

Carboxypeptidases are enzymes that hydrolyze C-terminal peptide bonds. The carboxypeptidase family includes metallo-, serine, and cysteine carboxypeptidases. According to their substrate specificity, these enzymes are referred to as carboxypeptidase A (cleaving aliphatic residues) or carboxypeptidase B (cleaving basic amino residues). The protein encoded by this gene is activated by trypsin and acts on carboxypeptidase B substrates. After thrombin activation, the mature protein downregulates fibrinolysis. Polymorphisms have been described for this gene and its promoter region. Alternate splicing results in multiple transcript variants. [provided by RefSeq, Jun 2013]

Canonical amino-acid sequenceUniProt

423 residues, UniProt reviewed canonical sequence.

>Q96IY4|CPB2
     1  MKLCSLAVLV PIVLFCEQHV FAFQSGQVLA ALPRTSRQVQ VLQNLTTTYE IVLWQPVTAD
    61  LIVKKKQVHF FVNASDVDNV KAHLNVSGIP CSVLLADVED LIQQQISNDT VSPRASASYY
   121  EQYHSLNEIY SWIEFITERH PDMLTKIHIG SSFEKYPLYV LKVSGKEQAA KNAIWIDCGI
   181  HAREWISPAF CLWFIGHITQ FYGIIGQYTN LLRLVDFYVM PVVNVDGYDY SWKKNRMWRK
   241  NRSFYANNHC IGTDLNRNFA SKHWCEEGAS SSSCSETYCG LYPESEPEVK AVASFLRRNI
   301  NQIKAYISMH SYSQHIVFPY SYTRSKSKDH EELSLVASEA VRAIEKISKN TRYTHGHGSE
   361  TLYLAPGGGD DWIYDLGIKY SFTIELRDTG TYGFLLPERY IKPTCREAFA AVSKIAWHVI
   421  RNV

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against CPB2 can act on the native protein depends on physical access: surface and secreted proteins are reachable by circulating antibodies, intracellular proteins usually are not.

Antibody reachability
Secreted
Secreted
Yes
Transmembrane segments
0
Mean surface accessibility (rSASA)
0.22
Highest tissue expression
1,387 nTPM

Expression across tissuesHPA

Tissue

  • liver: 1,387 nTPM
  • lung: 17 nTPM
  • epididymis: 6 nTPM
  • gallbladder: 4.5 nTPM
  • bone marrow: 0.4 nTPM
  • kidney: 0.4 nTPM

Single-cell type

  • hepatocytes: 1,724 nCPM
  • cholangiocytes: 230 nCPM
  • alveolar cells type 2: 77 nCPM
  • oligodendrocytes: 67 nCPM
  • oligodendrocyte progenitor cells: 22 nCPM
  • retinal horizontal cells: 12 nCPM

Immune cell

  • basophil: 0 nTPM
  • classical monocyte: 0 nTPM
  • eosinophil: 0 nTPM
  • gdT-cell: 0 nTPM
  • intermediate monocyte: 0 nTPM
  • MAIT T-cell: 0 nTPM

Brain region

  • white matter: 19 nTPM
  • basal ganglia: 16 nTPM
  • pons: 15 nTPM
  • midbrain: 14 nTPM
  • thalamus: 14 nTPM
  • medulla oblongata: 13 nTPM

Genetic constraint and essentialitygnomAD · DepMap

Does the body need this protein intact? Low LOEUF or a strong DepMap dependency means loss or blockade of the protein is likely to be felt.

gnomAD LOEUF (loss-of-function intolerance)
1.34
gnomAD pLI
0
gnomAD missense Z
0.95
DepMap mean gene effect
0.04
DepMap dependency class
none

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 2% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

Molecular functions

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads CPB2 as an antibody target. Whether an autoantibody or antibody against CPB2 could matter depends on whether native CPB2 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

CPB2 is annotated as secreted, so native CPB2 circulates and is directly accessible to antibodies. Secreted and cell-surface proteins are the autoantibody targets most likely to act like drugs, blocking or depleting the native protein.

Annotation status

The present source text does not explicitly label CPB2 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/CPB2. Study-independent annotations aggregated from UniProt, Human Protein Atlas, PubMed, IEDB, Pfam, InterPro, Gene Ontology, AlphaFold, gnomAD, DepMap, ClinVar, TCGA. Catalog release seroatlas-reviewed-human-uniprot-20260313.

Seroatlas is the reference for exploring autoantibody and antibody serology at the human-protein level: the autoreactome and human serome, multiplex serology (HuProt, HuScan, VirScan, PhIP-Seq).

© 2026 · Seroatlas, Discover Oregon LLC · Terms of use

Loading the interactive Seroatlas protein explorer...