benzoyl-L-tyrosyl-[1-13C]alanine

Benzoyl-L-tyrosyl-[1-13C]alanine is a synthetic 13C-labeled dipeptide diagnostic agent designed to evaluate pancreatic exocrine function through breath analysis. Upon oral administration, the substance reaches the duodenum where it acts as a specific substrate for **chymotrypsin**, a protease secreted by the exocrine pancreas. Chymotrypsin cleaves the peptide bond between the tyrosine and the 13C-labeled alanine residues. The released [1-13C]alanine is subsequently absorbed by the intestinal mucosa and metabolized in the liver, leading to the production of 13CO2. This labeled carbon dioxide is transported to the lungs and exhaled, where the ratio of 13CO2 to 12CO2 can be measured using infrared spectroscopy or mass spectrometry (often utilizing the BreathID system). A reduced rate of 13CO2 excretion indicates impaired chymotrypsin secretion, which is a hallmark of pancreatic exocrine insufficiency (PEI) in conditions such as chronic pancreatitis and cystic fibrosis.

Brand names

BreathID

Other names

benzoyl-L-tyrosyl-13C-alaninebenzoyl-L-tyrosyl13C-alaninebenzoyl-L-tyrosyl 13C-alanineN-benzoyl-L-tyrosyl-[1-13C]alanine13C-labeled benzoyl-tyrosyl-alanine