On the Measurement and the Expression ofBuffer Capacity by the Electrical Method

　物質溶液の緩衝能の測定並びに表示法について、緩衝能の加成性の実験を行って検討した結果、緩衝能曲線による表示法は極めて具体的、合理的であり、物質溶液の緩衝能の実態を解明するためには緩衝能曲線を利用することが極めて必要であることを認めた。また全緩衝能の表示法として緩衝能曲線を利用する面積法とpH変化曲線を利用する滴定法についても検討した。　終りに臨み、本実験に御協力を頂いた鳥取県工業試験場長佐藤友清氏、本学々生藪木聡博、安藤光子両君に深く感謝いたします

On the Buffer Caoacities of peptides and Amino Acids as Amphoteric Electrolytes (Ⅰ) On the Buffer Capacities of Amino Acids

The author studied on the buffer capacity of amino acid as an amphoteric electrolyte by electrical method. The results abtained are as follows: 1) Most α―amino acids do not show buffer activities in the range of pH 4.5~7.5, and have the maximum buffer value in the range of pH 9.0~10.0. 2) β―,γ― and acidic amino acids show strong buffer activities at pH below 6.0, and have the maximum value at about pH 4.0. 3)It is a peculiar fact that histidine shows a buffer activity in the range of pH 3.0~11.0, and has higher values at about pH 6.0 and 9.5, respectively

On the Formation of Amines by Lactic Acid Bacteria

Formation and degradation of amines by lactic acid bacteria in Sake-brewing were studied. Tyramine and two kinds of guanidine compounds were produced by lactic acid bacteria, i. e., Lactobacillus Sake and Leuconostoc mesenterioides var. Sake, in cultures on Koji-extract. Several kinds of amines were detected in the cell-free extract of bacteria harvested from cultures on koji-extract. They were : iso-butylamine, cadaverine and four kinds of ninhydrine-positive substances. In the course of autolysis of the bacterial cell, some of them showed a decreasing tendency in amount. From these facts, it is considered to be possible that lactic acid bacteria play an important role in amine formation and degradation in Sake-brewing