Pectate transition

The effect on the conformational-aggrega-tlonal properties of pectate in aqueous solution brought by the addition of specific ions (H+, Ca +. Cu +) was studied by osmometric, microcalorimetric, dilato-metric, and rheological methods. Evidence is provided for the intramolecular nature of the pH induced conformational transition. The addition of divalent ions brings about at the same time a conformational change of the chain of pectate and chain-chain association. 

The results presented here on pectate solutions containing calcium or copper ions bring interesting evidence for an anomalous behavior of pectate properties in the range of ion to polymer ratio below that corresponding to the massive phase separation. The possibility that a conformational change proceeds along with the interaction with divalent ions is examined and discussed in comparison with the case of the proton-induced conformational transition. 

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