Interaction between xanthurenic acid-insulin complex and zinc ions.
An equimolar mixture of a xanthurenic acid-insulin complex and ZnSO4 was separated into an insulin peak and a peak containing xanthurenic acid (XA) and Zn by Sephadex G-75 column chromatograpy. XA and di-[L-histidino]-zinc (II) readily combined to produce di-[L-histidino]-di-xanthurenato zinc (II) (His2-Zn2+-XA2). By increase in the concentration of Zn2+ ions, XA was removed from di-[L-histidino]-di-xanthurenato zinc (II) (His2-Zn2+-XA2) as XA-Zn2+. The XA-insulin complex showed dcreased relative intensity of fluorescence compared with the Zn-insulin when excited at a wavelength of 284 nm. The difference spectrum between native Zn-insulin and XA-insulin complexes showed a slight red shift. A diffference in the CD spectrum between native Zn-insulin and XA-insulin complexes was observed.
D001665:Binding Sites; D002850:Chromatography, Gel; D002942:Circular Dichroism; D004151:Dipeptides; D006639:Histidine; D007328:Insulin; D011485:Protein Binding; D013053:Spectrophotometry; D014977:Xanthurenates; D015032:Zinc
D004151:Dipeptides; D007328:Insulin; D014977:Xanthurenates; D006639:Histidine; D015032:Zinc