Del Duca S, Beninati S, Serafini-Fracassini D
Department of Biology E. S., University of Bologna, Italy.
Biochem J. 1995 Jan 1;305 ( Pt 1)(Pt 1):233-7. doi: 10.1042/bj3050233.
Incubation of chloroplasts of Helianthus tuberosus with labelled putrescine and/or spermidine and proteolytic digestion of their trichloroacetate-soluble and -insoluble proteins revealed the presence of N-(gamma-glutamyl)-putrescine, N1,N4-bis-(gamma-glutamyl)-putrescine and N1,N8-bis-(gamma-glutamyl)spermidine. This finding may be regarded as unequivocal proof of the presence of transglutaminase activity in chloroplasts. In addition, the recovery of spermidine or putrescine and acetylspermidine from chloroplasts incubated with [3H]putrescine or [3H]spermidine respectively indicates the existence of biosynthetic and oxidative pathways. These results suggest that polyamines may have an important function in chloroplasts both in their free form and by covalently binding to proteins.
用标记的腐胺和/或亚精胺孵育菊芋叶绿体,并对其可溶于三氯乙酸和不溶于三氯乙酸的蛋白质进行蛋白酶消化,结果显示存在N-(γ-谷氨酰基)-腐胺、N1,N4-双-(γ-谷氨酰基)-腐胺和N1,N8-双-(γ-谷氨酰基)亚精胺。这一发现可被视为叶绿体中存在转谷氨酰胺酶活性的确凿证据。此外,分别用[3H]腐胺或[3H]亚精胺孵育叶绿体后,从叶绿体中回收亚精胺或腐胺以及乙酰亚精胺,这表明存在生物合成和氧化途径。这些结果表明,多胺可能在叶绿体中以游离形式以及通过与蛋白质共价结合发挥重要作用。