Seroatlas · Human Serome Atlas

CPB1

Carboxypeptidase B

Also known as: CBPB1_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
P15086
Gene
CPB1
Ensembl
ENSG00000153002
Chromosome
3
Canonical length
417 aa
Protein class
Enzymes, Plasma proteins, Predicted secreted proteins
Subcellular location
Endoplasmic reticulum
Secretome location
Secreted to digestive system

OverviewNCBI Gene

Three different procarboxypeptidases A and two different procarboxypeptidases B have been isolated. The B1 and B2 forms differ from each other mainly in isoelectric point. Carboxypeptidase B1 is a highly tissue-specific protein and is a useful serum marker for acute pancreatitis and dysfunction of pancreatic transplants. It is not elevated in pancreatic carcinoma. [provided by RefSeq, Jul 2008]

Canonical amino-acid sequenceUniProt

417 residues, UniProt reviewed canonical sequence.

>P15086|CPB1
     1  MLALLVLVTV ALASAHHGGE HFEGEKVFRV NVEDENHINI IRELASTTQI DFWKPDSVTQ
    61  IKPHSTVDFR VKAEDTVTVE NVLKQNELQY KVLISNLRNV VEAQFDSRVR ATGHSYEKYN
   121  KWETIEAWTQ QVATENPALI SRSVIGTTFE GRAIYLLKVG KAGQNKPAIF MDCGFHAREW
   181  ISPAFCQWFV REAVRTYGRE IQVTELLDKL DFYVLPVLNI DGYIYTWTKS RFWRKTRSTH
   241  TGSSCIGTDP NRNFDAGWCE IGASRNPCDE TYCGPAAESE KETKALADFI RNKLSSIKAY
   301  LTIHSYSQMM IYPYSYAYKL GENNAELNAL AKATVKELAS LHGTKYTYGP GATTIYPAAG
   361  GSDDWAYDQG IRYSFTFELR DTGRYGFLLP ESQIRATCEE TFLAIKYVAS YVLEHLY

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against CPB1 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)
0.23
Highest tissue expression
213,987 nTPM

Expression across tissuesHPA

Tissue

  • pancreas: 213,987 nTPM
  • adrenal gland: 79 nTPM
  • breast: 74 nTPM
  • ovary: 46 nTPM
  • heart muscle: 38 nTPM
  • salivary gland: 34 nTPM

Single-cell type

  • pancreatic acinar cells: 35,500 nCPM
  • mesothelial cells: 347 nCPM
  • megakaryocyte-erythroid progenitors: 228 nCPM
  • pancreatic duct cells: 159 nCPM
  • decidual stromal cells: 101 nCPM
  • erythrocyte progenitors: 78 nCPM

Immune cell

  • basophil: 4 nTPM
  • neutrophil: 1.8 nTPM
  • naive CD8 T-cell: 1.4 nTPM
  • NK-cell: 1.4 nTPM
  • gdT-cell: 1.3 nTPM
  • memory CD8 T-cell: 1.1 nTPM

Brain region

  • white matter: 6.7 nTPM
  • basal ganglia: 3.5 nTPM
  • cerebral cortex: 3.3 nTPM
  • midbrain: 2.7 nTPM
  • thalamus: 2.5 nTPM
  • pons: 2.4 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about CPB1.

Disease | ImmuneIEDB

Conditions an epitope on CPB1 was assayed in.

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)
1.63
gnomAD pLI
0
gnomAD missense Z
0.34
DepMap mean gene effect
0.03
DepMap dependency class
selective

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 CPB1 as an antibody target. Whether an autoantibody or antibody against CPB1 could matter depends on whether native CPB1 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

CPB1 is annotated as secreted, so native CPB1 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 CPB1 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/CPB1. 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...