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The capillary electrophoretic (CE) separation of the inorganic anions bromide, chloride, nitrate, nitrite, fluoride, sulfate and phosphate is described in 0.005 mol/L sodium chromate electrolyte in the presence of soluble polydisperse ionic polymers (polyelectrolytes). The cationic polyelectrolytes used were as follows: poly(1,1-dimethyl-3,5-dimethylenepiperidinium) chromate, hexadimethrine chromate, poly(1,1-dimethyl-3,5-dimethylenepyrrolidinium) chromate and ((diethylamino)ethyl)-dextran chromate in the concentration range 0.004-0.6% (w/v). These polyelectrolytes were shown to be capable of reversing the direction of the electroosmotic flow as well as inducing changes in analyte electrophoretic mobility, separation selectivity, and resolution. Changes in electrophoretic mobility by as much as 25% were observed for the sulfate anion, and the resolution of fluoride and phosphate was enhanced by a factor of 7.8. In the presence of 0.05-0.17% w/v poly(1,1-dimethyl-3,5-dimethylenepyrrolidinium) chromate at pH 8, separation currents were found to increase only slightly as compared to an electrolyte containing equivalent amounts of sodium chromate. Electroosmotic flow was also found to be fairly constant (+/- 16%) in the pH range 6.55-10.02 for 0.01% (w/v) poly(1,1-dimethyl-3,5-dimethylenepiperidinium) chromate at an ionic strength of 0.04, compared to a 400% change in the absence of the polyelectrolyte. The reproducibility of the electroosmotic mobility was between 0.36 and 6% RSD, and analyte electrophoretic mobility was between 0.01 and 1.6% RSD. Peak height reproducibility was 0.2-8.0% RSD. Separation efficiencies were between 258,000 and 780,000 theoretical plates, and detection limits were between 4.4 x 10(-7) and 9.1 x 10(-6) mol/L.

The antifreeze polypeptides (AFPs) are found in several marine fish and have been grouped into four distinct biochemical classes (type I-IV). Recently, the new subclass of skin-type, type I AFPs that are produced intracellularly as mature polypeptides have been identified in the winter flounder (Pleuronectes americanus) and the shorthorn sculpin (Myoxocephalus scorpius). This study demonstrates the presence of skin-type AFPs in the longhorn sculpin (Myoxocephalus octodecemspinosus), which produces type IV serum AFPs. Using polymerase chain reaction-based methods, a clone that encoded for a type I AFP was identified. The clone lacked a signal sequence, indicating that the mature polypeptide is produced in the cytosol. A recombinant protein was produced in Escherichia coli and antifreeze activity was characterized. Four individual Ala-rich polypeptides with antifreeze activity were isolated from the skin tissue. One polypeptide was completely sequenced by tandem MS. This study provides the first evidence of a fish species that produces two different biochemical classes of antifreeze proteins (type I and type IV), and enforces the notion that skin-type AFPs are a widespread biological phenomenon in fish.

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