CELA3A (chymotrypsin-like elastase 3A) is a pancreatic digestive enzyme that functions as a serine-type endopeptidase with efficient protease activity and alanine specificity, though with limited elastolytic activity 1. The protein is secreted by the human pancreas as a proenzyme (proCELA3A) and shares 92% sequence identity with CELA3B, arising from gene duplication 2. Unlike CELA3B, CELA3A forms only weak complexes with procarboxypeptidase A1 due to an evolutionary amino acid substitution (Ala241→Gly), which affects zymogen stability and activation control 3. CELA3A serves as a biomarker for pancreatic exocrine function and is detected by commercial fecal elastase tests, though with lower efficiency than CELA3B 1. The gene shows polymorphic variation at position 241, but these variants do not significantly alter chr1 pancreatitis risk 2. Clinically, CELA3A expression levels in plasma extracellular vesicles have emerged as potential biomarkers for diabetic retinopathy progression 4, and it is downregulated in pancreatic ductal adenocarcinoma, making it a potential hub gene for drug discovery approaches 5. The protein's tissue-specific expression pattern makes it susceptible to cross-contamination in RNA sequencing datasets 6.