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标题：Pentamines as Substrate for Human Spermine Oxidase
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作者：Koichi Takao ; Akira Shirahata ; Keijiro Samejima 等
期刊名称：Biological and Pharmaceutical Bulletin
印刷版ISSN：0918-6158
电子版ISSN：1347-5215
出版年度：2013
卷号：36
期号：3
页码：407-411
DOI：10.1248/bpb.b12-00818
出版社：The Pharmaceutical Society of Japan
摘要：Substrate activities of various linear polyamines to human spermine oxidase ( h SMO) were investigated. The activities were evaluated by monitoring the amount of H₂O₂ released from sample polyamines by h SMO. H₂O₂ was measured by a HPLC method that analyzed fluorescent dimers derived from the oxidation of homovanillic acid in the presence of horseradish peroxidase. Six triamines were tested and were found not to be h SMO substrates. Of sixteen tetramines tested, spermine (Spm) was the most active substrate, followed by homospermine and N -butylated Spm. Pentamines showed a characteristic pattern of substrate activity. Of thirteen pentamines tested, 3343 showed higher substrate activity than Spm, and 4343 showed similar activity to Spm. The activities of the other pentamines were as follows: 3443, 4443, 4344, 3344, 4334, 4444, and 3334 (in decreasing order). Product amines released from these pentamines by h SMO were then analyzed by HPLC. Triamine was the only observed product, and the amount of triamine was nearly equivalent to that of released H₂O₂. A marked difference in the pH dependency curves between tetramines and pentamines suggested that h SMO favored reactions with a non-protonated secondary nitrogen at the cleavage site. The K _m and V _max values for Spm and 3343 at pH 7.0 and 9.0 were consistent with the higher substrate activity of 3343 compared to Spm, as well as with the concept of a non-protonated secondary nitrogen at the cleavage site being preferred, and 3343 was well degraded at a physiological pH by h SMO.
关键词：spermine oxidase;polyamine;pentamine;hydrogen peroxide;homovanillic acid