Preparation of fractionated low-molecular-weight poly(S-carboxymethyl-L-cysteine) by ion-exchange chromatography
✍ Scribed by Hiroshi Maeda; Takeshi Ito; Hidetoshi Suzuki; Shuzo Hirata; Isao Kako; Masachika Yoshino; Shoichi Ikeda; Yuji Kobayashi
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1983
- Tongue
- English
- Weight
- 849 KB
- Volume
- 22
- Category
- Article
- ISSN
- 0006-3525
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✦ Synopsis
Synopsis
N-Carboxyanhydride of S-carbobenzoxymethyl-L-cysteine was polymerized by the addition of ethylamine as an initiator a t anhydride-initiator ratios AII = 3,4,6,8,12, and 16. Acetylation of the amino terminal was carried out with p-nitrophenylacetate. After debenzylation, low-molecular-weight samples of poly(S-carboxymethyl-r.-cysteine) were obtained for AII = 8, 12, and 16. These samples were fractionated by ion-exchange chromatography (DEAE-cellulose). About six fractions of narrow molecular-weight distributions were obtained. Their degrees of polymerization (DP) ranged from 8 to 16, as determined from proton nmr and also estimated based on their elution volumes on the ion-exchange chromatography a t constant ionic strengths. This range of DP covered the range of interest concerning the formation of the ,&structure in aqueous solutions; a fraction did not form the @-structure, whereas another fraction did. The results of the gel filtration (Biogel P-10) of the fractionated samples were consistent with the estimated DPs.