魚体表面の粘性物質に関する研究-IX : ドジョウの体表面粘性物質中のsialic acidについて

概要

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No detailed work has been done on positive substances for p-dimethylaminobenzaldehyde (the so-called “direct EHRLICH reaction”) and orcinol (BIALs reagent) etc. in the external mucous substance of fish, though there have been a few reports describing the presence and the amount of them. In order to clarify the chemical properties of these substances, the authors studied on the external mucous substance of loath. The isolation procedure is shown in Fig. 1. Crystallization was performed from water-methanol to which ethyl ether was added. The dry material shown in Fig. 1 was dissolved in a small amount of water and then methanol 10 times as much as the water was added to it. Ethyl ether was added in small portions during several days. The occurring amorphous precipitate was filtered off. When the amorphous precipitate disappeared, ethyl ether was added until a faint turbidity appeared. The slender needle-like crystal (Fig. 2) was obtained by standing the turbid solution at room temperature. Judging from the results, i. e. decomposition point (176-179°C), 5 kinds of absorption spectra (Fig. 3), paper chromatogram (Table 1) and infrared spectrum (Fig. 4), the crystal was identified as N-acetylneuraminic acid.