The self-association of glycosyl phenylazo dyes (Yariv antigens)

Abstract

The aggregation of tris(4-glycosyloxyphenylazo)phloroglucinol compounds (Yariv antigens) where glyco = β-D-gluco, β-D-manno, β-D-galacto and α- D-galacto has been investigated by equilibrium sedimentation, the photoelectric scanning absorption optical system being utilized. The compounds have been shown to undergo a strong self-association in water and an analysis procedure employing Laplace transforms indicated a very wide distribution of species in the ultracentrifuge cell at equilibrium. To determine the type of association the concentration of monomer as a function of total weight concentration was calculated by using the recently developed Ω function. When the concentration of monomer is very low, as in the present case, the analysis is difficult because very slight curvature in the Ω-function plot has a large effect on the extrapolation to zero concentration. ��� The results are best described by an isodesmic indefinite self- association. The β-glucoside Yariv antigen was the most extensively investigated and the most highly purified sample was shown to have an association constant of 2.5 x 107 l. mol-1. The order of the association constants of the Yariv compounds was found to be β-glucoside > β- galactoside > α-galactoside > β-mannoside. For the β-glucoside compound an increase in temperature favours species of lower molecular weight, and from the enthalpy change a positive entropy change for the association is indicated. The compounds are disaggregated by concentrated solutions of urea and guanidine hydrochloride. Spectral measurements on the β-glucoside compound indicate disaggregation by sodium dodecyl sulfate above the critical micelle concentration.

Yariv reagent treatment induces programmed cell death in Arabidopsis cell cultures and implicates arabinogalactan protein involvement

“…Yariv reagents strongly self‐associate in aqueous solutions to form complexes of 10–50 molecules ( Woods et al . 1978 ) with an apparent molecular weight range of 10–50 kDa, most of which should be small enough to enter cell walls ( Carpita et al .…”

β-Galactosyl Yariv Reagent Binds to the β-1,3-Galactan of Arabinogalactan Proteins

“…The inside cavity of the helix is relatively hydrophobic and therefore a candidate site for hydrophobic interaction with the phenylazotrihydroxybenzene core of b-Yarivs. A previous equilibrium sedimentation analysis has demonstrated strong self-association of Yariv phenylglycosides in water (Yariv et al, 1962;Woods et al, 1978). Further Yariv hydrophobic interactions, therefore, may cause the formation of large insoluble b-1,3-galactan-Yariv complexes.…”

Effects of Yariv phenylglycosides onRosa cell suspensions: Evidence for the involvement of arabinogalactan-proteins in cell proliferation

“…We reasoned that several characteristics of Yariv phenylglycosides would facilitate our study. In aqueous medium, Yariv phenylglycosides strongly self-associate to form complexes of 20-30 kDa (Woods et al 1978) which should be small enough to enable their passage through cell wall pores (Carpita et al 1979) but large enough to restrict their passage through the plasma membrane. Furthermore, Yariv phenylglycosides having sugars linked in 0~-anomeric configuration or with cis hydroxyl or other substitutions on C2 of the 13-D-glycopyranosyl determinant (Jermyn 1978;Nothnagel and Lyon 1986) do not bind to AGPs and thus should be valuable controls to distinguish nonspecific effects.…”