Fluorescence Assay of Proline: Competitive Inhibition of Fluorescamine Reaction

Abstract

The rate of reaction of fluorescamine with proline is faster than with primary amino acids. Proline competitively inhibits the fluorogenic reaction of primary amines with fluorescamine, the degree of inhibition being proportional to the amount of proline. Under the conditions described, 5×10⁻⁷ M proline produces a 10% diminution of fluorescence. An assay of proline or hydroxyproline based on fluorescence inhibition would be more sensitive than colorimetric assays based on ninhydrin or fluorescamine.

Key Words:

• fluorescence assay
• fluorescamine
• proline