Disulfide bonds of bovine serum albumin and wool were reduced by n-tributylphosphine to sulfhydryl groups that were then modified by methyl or ethyl vinyl sulfone in a nucleophilic addition reaction to S-(beta-ethylsulfonylmethyl)-L-cysteine and S(beta-ethylsulfonylethyl)-L-cysteine, respectively. The reductive alkylation was carried out either simultaneously, with both the reducing and alkylating agents present in the reaction mixture, or sequentially, with the reduced proteins first isolated before alkylation. Amino acid analysis studies showed that authentic, synthetic S-(beta-ethylsulfonylethyl)-L-cysteine eluted as a well-resolved peak after serine but that the peak associated with the corresponding methyl derivative overlapped the corresponding peak due to threonine. The extent of alkylation of the sulfhydryl groups of cysteine, epsilon-NH2 of lysine, and NH groups of the imidazole ring of histidine was also measured by amino acid analysis. The results show that alkyl vinyl sulfones have a strong chemical affinity for protein functional groups.

SynopsisThe binding of mercuric chloride and other metal salts to bark, activated sludge (Milorganite), chitosan, poly(p-aminostyrene), and other natural and synthetic materials was investigated by specific atomic absorption and x-ray fluorescence spectroscopy. The synthetic poly(amin0styrene) was included for comparison with the natural polyamine chitosan. Our results show that a wide range of natural materials are potentially useful for the removal of toxic and precious metals that may be present in industrial effluents, mine waters, or other water supply. Such metal salts include those of mercury, lead,

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A survey was carried out with the aid of X-ray fluorescence and atomic absorption spectroscopy on binding of various metal cations to wool from aqueous media. The results show that wool removes at a rapid rate a number of toxic and industrial metals. These include mercury, cadmium, zinc, antimony, bismuth, tin, lead, silver, platinum, palladium, and uranium cations. Because of its insolubility, wool facilitates anion and cation uptake analysis and is, therefore, a versatile model for protein-metal interaction studies.