Fluorescent Substrates for Polyamine Catabolic Enzymes and Transport

Abstract

The most widely used methods for measuring polyamine enzyme activities are radioisotope methods that measure the radioactivity of compounds produced from radiolabeled substrate by the enzyme reaction. Several fluorescent polyamines have been developed for the measurement of the polyamine transport system (PTS) or transglutaminase. Although fluorophores in the fluorescent polyamines may affect the affinity of the polyamine moiety to the enzyme protein, the assays that use fluorescent substrate are sensitive and simple for common laboratory usage.In this chapter, the uses of dansyl polyamines with a simple high-performance liquid chromatography system for the measurement of the PTS and polyamine catabolic enzymes including spermidine/spermine N¹-acetyltransferase and N¹-acetylpolyamine oxidase are described.

Transport of a Fluorescent Analogue of Glucose (2-NBDG) versus Radiolabeled Sugars by Rumen Bacteria and Escherichia coli

“…Kinetics of solute transport traditionally have been measured with radiolabeled tracers. , Over the past two decades, transport has also been measured with fluorescently labeled tracers, including analogues of glucose, − other monosaccharides, trehalose, amino acids, , peptides, toluene, and polyamines . Some fluorescent tracers are not labeled analogues but are naturally fluorescent compounds that fortuitously are transported by a transporter system of interest; for example, esculin is transported by type I plant sucrose transporters .…”

“…1,2 Over the past two decades, transport has also been measured with fluorescently labeled tracers, including analogues of glucose, 3−6 other monosaccharides, 7 trehalose, 8 amino acids, 9,10 peptides, 11 toluene, 12 and polyamines. 13 Some fluorescent tracers are not labeled analogues but are naturally fluorescent compounds that fortuitously are transported by a transporter system of interest; for example, esculin is transported by type I plant sucrose transporters. 14 These fluorescent tracers offer certain advantages over their radiolabeled counterparts, such as (i) being compatible with fluorescent techniques (e.g., microscopy and flow cytometry), (ii) being adaptable to single, living cells, and (iii) not requiring use of radioactive facilities.…”