The putrescine-biosynthesis pathway in Tetrahymena thermophila was delineated by studying crude extracts prepared from exponentially growing cultures. A pyridoxal phosphate-stimulated ornithine decarboxylase activity competitively inhibited by putrescine was detected. CO2 was also liberated from L-arginine, but analyses by t.l.c. and enzyme studies suggested that the activity was not due to arginine decarboxylase, nor could enzyme activities converting agmatine into putrescine be detected. We conclude that the decarboxylation of L-ornithine is probably the only major route for putrescine biosynthesis in this organism during exponential growth.
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机译:通过研究从指数生长的培养物制备的粗提物,描绘了嗜热四膜虫中的腐胺生物合成途径。检测到由腐胺竞争性抑制的吡ido醛磷酸刺激的鸟氨酸脱羧酶活性。 L 2-精氨酸也释放出CO 2,但通过t.l.c分析。酶研究表明该活性不是由于精氨酸脱羧酶引起的,也没有检测到将胍丁胺转化为腐胺的酶活性。我们得出结论,L-鸟氨酸的脱羧可能是该生物在指数生长过程中腐胺生物合成的唯一主要途径。
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