著者

鈴木 厚子 福井 美園 中安 寿美子 滝谷 玲子 多田 敬三

出版者

慶應義塾大学

雑誌

共立薬科大学研究年報 (ISSN:04529731)

巻号頁・発行日

vol.28, pp.1-15, 1984-03-25

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The reaction of N-nitroso-N-butylurea (NBU) with an equivalent of L-α-aminoacid was made in the buffer solution of pH 7.2 at 37℃ for 3 weeks. α-Carbamoyl-aminoacid was isolated and identified for each α-aminoacid examined together with the decomposition-products of NBU such as 1-and 2-butanols, urea and a slight amount of butylurea. A quantitative research was also carried out for L-methionine and L-leucine by high performance liquidchromatography. It was found that about 60% of L-methionine and 53% of L-leucine was carbamoylated respectively with an equivalent of NBU during 5 days, but, thereafter, no appreciable further carbamoylation was observed, and also that 83% of methionine reacted with twice equivalent of NBU. The velocity and products of decomposition of NBU in the buffer solutions of various pH were reinvestigated. The minimum rate constant for the apparent first-order decomposition was found in the region of pH3. The determination of butanols produced by gaschromatography of ether extracts from the reaction mixture showed that not only their total amounts were practically unvaried but also the ratio of 1-butanol to 2-butanol was almost equal value of 2.0 in various pH regions. The amount of urea or butylurea produced in each pH solution was relatively estimated by semiquantitative thin-layer chromatography. In the case of urea, no appreciable difference was observed except in the regions of pH3 and pH4,where urea was found to be a minor product and, instead, an unknown product was detected, whereas the formation of butylurea was slight in higher pH regions than pH5,however, in more acidic medium denitrosation seemed to be considerable although it might be a side reaction in the whole decomposition-pathway. Some considerations and discussions were made on the mechanism of decomposition of NBU, and also on the results from the quantitative study for the reaction of NBU with α-aminoacids.