CELA3B

Chymotrypsin-like elastase family member 3B also known as elastase-3B, protease E, or fecal elastase is an enzyme that in humans is encoded by the CELA3B gene.^[5][6][7]

CELA3B
Identifiers
Aliases	CELA3B, CBPP, E1, EL-1, ELA3B, chymotrypsin like elastase family member 3B, chymotrypsin like elastase 3B
External IDs	MGI: 1915118; HomoloGene: 128227; GeneCards: CELA3B; OMA:CELA3B - orthologs
Gene location (Human) Chr. Chromosome 1 (human)[1] Band 1p36.12 Start 21,977,022 bp[1] End 21,998,642 bp[1]
Gene location (Mouse) Chr. Chromosome 4 (mouse)[2] Band 4 D3|4 69.9 cM Start 137,148,310 bp[2] End 137,157,851 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in body of pancreas islet of Langerhans testicle body of stomach fundus duodenum ectocervix right coronary artery right lobe of liver placenta Top expressed in pyloric antrum islet of Langerhans duodenum sexually immature organism morula embryo esophagus brown adipose tissue gastric mucosa mucous cell of stomach More reference expression data BioGPS n/a
Gene ontology Molecular function peptidase activity serine-type peptidase activity hydrolase activity serine-type endopeptidase activity Cellular component extracellular space Biological process proteolysis Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 23436 67868 Ensembl ENSG00000219073 ENSMUSG00000023433 UniProt P08861 Q9CQ52 RefSeq (mRNA) NM_007352 NM_026419 RefSeq (protein) NP_031378 NP_080695 Location (UCSC) Chr 1: 21.98 – 22 Mb Chr 4: 137.15 – 137.16 Mb PubMed search [3] [4]
Wikidata
View/Edit Human View/Edit Mouse

Clinical literature that describes human elastase 1 activity in the pancreas or fecal material is actually referring to chymotrypsin-like elastase family member 3B (i.e. the enzyme / protein this article focuses on).^[8]

Function

Elastases form a subfamily of serine proteases that hydrolyze many proteins in addition to elastin. Humans have six elastase genes which encode the structurally similar proteins elastase 1, 2, 2A, 2B, 3A, and 3B. Unlike other elastases, elastase 3B has little elastolytic activity. Like most of the human elastases, elastase 3B is secreted from the pancreas as a zymogen and, like other serine proteases such as trypsin, chymotrypsin and kallikrein, it has a digestive function in the intestine. Elastase 3B preferentially cleaves proteins after alanine residues. Elastase 3B may also function in the intestinal transport and metabolism of cholesterol. Both elastase 3A and elastase 3B have been referred to as protease E and as elastase 1, and excretion of this protein in fecal material is frequently used as a measure of pancreatic function in clinical assays.^[7]

Clinical significance

Fecal elastase is a medical test that measures how well the pancreas is functioning.

The fecal elastase test measures the concentration of the elastase-3B enzyme found in fecal matter with an enzyme-linked immunosorbent assay (ELISA). Results of this test can give a good indication of exocrine pancreatic status, and the test is less invasive and expensive than the current "gold standard", secretin-cholecystokinin test.^[9] Levels of fecal elastase lower than 200 μg / g of stool indicate an exocrine insufficiency. Correlations between low levels and chronic pancreatitis^[10] and cancer^{[citation needed]} have been reported.