Collect. Czech. Chem. Commun. 1988, 53, 2833-2842

Complexation of poly(Lys-Ala) and poly(Lys-Ala-Ala-Ala) with pectins and potassium oligogalacturonates

Slavomír Bystrickýa, Anna Malovíkováa, Tibor Sticzaya and Karel Bláhab

a Institute of Chemistry, Centre for Chemical Research, Slovak Academy of Sciences, 842 38 Bratislava
b Institute of Organic Chemistry and Biochemistry, Czechoslovak Academy of Sciences, 166 10 Prague 6


The selected model polypeptides poly(Lys-Ala) and poly(Lys-Ala-Ala-Ala) underwent a helix-forming interaction with potassium pectates and pectinates of various esterification degree (E) and with some potassium oligogalacturonates (n = 2-5, 9, 13). Formation of the complex quantitatively monitored by a circular dichroic measurement showed that the specific band distribution of charged side chains of lysine units at the surface of helical structure does not constitute grounds for the local mode of interaction. Potassium pectinate of esterification degree E 57%, corresponding to polypeptides by charge density, does not reveal enhanced complexation values. The complex-forming efficacy continuously decreases with the increase of the esterification degree of pectin. Saturation of charges of the polypeptide was achieved predominantly by the spatial action of the superhelical structure of D-galacturonate chains.