ISSN:
1432-1017
Keywords:
Xanthan
;
conductivity
;
polyelectrolyte
;
conformation
;
polysaccharide
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Physics
Notes:
Abstract The conductivity of xanthan (extracellular polysaccharide from Xanthomonas campestris) in the potassium salt form has been studied over the temperature range 5–80°C spanning the order-disorder conformational transition. In salt-free solution data analysis using Manning's polyelectrolyte-conductivity theory gives a charge spacing, b, of 0.58±0.04 nm for the low temperature ordered form, consistent with a single rather than a double helix (b=0.58 and 0.29 nm respectively). In solutions with 0.01 M added KBr the increase in counterion condensation on conformational ordering is found from conductivity studies to be — Δξ−1= 0.20 ± 0.02, in good agreement with the value 0.20±0.02 using polyelectrolyte-equilibrium theory for the variation of transition-midpoint temperature with added salt determined from opticalrotation data.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00263683
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