Determination of the transglycosidation activity of NAD+ glycohydrolases with 4-(2′-alkyl-sulfanyl-vinyl)-pyridine derivatives generating chromophoric NAD+ analogs

The base exchange of nicotinamide with pyridine derivatives 1a–5a, catalyzed by pig brain NAD+ glycohydrolase and ADP-ribosyl cyclase from Aplysia californica, generated the corresponding NAD+ analogs 1b–5b. These analogs exhibited a high absorbance band in the visible region. The transglycosidation rate was determined by monitoring the absorbance increase. Among the tested derivatives, (E)-4-[2-(methylsulfanyl)-vinyl]-pyridine 1a was the most suitable substrate for pig brain NAD+ glycohydrolase while 4-[1,3]-dithiolan-2-ylidenemethyl-pyridine 3a was the most efficient for ADP–ribosyl cyclase from A. californica.