5-Hydroxyindoleacetic acid (5HIAA) is a breakdown product of serotonin that is excreted in the urine. Serotonin and 5HIAA are produced in excess amounts by carcinoid tumors and levels of these substances may be measured in the urine to test for carcinoid tumors (NCI).

Neurotensin, guinea pig

Amyloid β-Protein (3-42) is the precursor of Pyr peptide. Pyroglutamate-modified Aβ (pEAβ) (3-42) is the core of the amyloid template block in Alzheimer's disease. pEAβ(3-42) accelerated the aggregation of Aβ(1-42), while Aβ(1-42) significantly slowed the primary and secondary nucleation of pEAβ(3-42).