1957 年 77 巻 9 号 p. 955-959
The principle (MG) giving positive Mainini reaction, isolated from human placental villus membrane and considered to be approximately uniform according to electrophoresis and ultracentrifugation, was submitted to oxidation by performic acid to find where cystine, one of the composite amino acids, is situated in the MG molecule and to find its relation to the efficacy. The oxidation product was further reduced to sever the -S-S- bond and various changes attendant in this reaction were examined. It was thereby assumed that cystine is not in the terminal position in the MG molecule, that -S-S- bond is necessary for the appearance of the effect, and that MG molecule is formed by the bonding of an open polypeptide chain through the -S-S- bond of cystine. Further, in order to find a part of chemical structure of MG, its terminal amino acids were examined by the DNP and carboxypeptidase methods and it was determined that its N-terminal amino acid is valine and C-terminal amino acid, leucine.