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ATP:AMP phosphotransferase activity, a new characteristic of Catharanthus roseus tonoplasts
Author(s) -
Hill M.,
Dupaix A.,
Nhiri M.,
Guyen L.,
Arrio B.
Publication year - 1988
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(88)80639-2
Subject(s) - catharanthus roseus , phosphotransferase , biochemistry , cytosol , vacuole , atpase , nucleotide , atp hydrolysis , atp–adp translocase , vesicle , adenylate kinase , adenine nucleotide , microsome , chemistry , enzyme , biology , cytoplasm , membrane , inner mitochondrial membrane , gene
The ATPase activity of Catharanthus roseus tonoplasts was examined using HPLC separation and quantification of adenine nucleotides. ATP seemed to be degraded into ADP and AMP by tonoplast vesicles. When ADP was the initial substrate, the appearance of AMP and concomitant ATP synthesis were observed; these reactions were inhibited by Ap 5 A. The apparent degradation of ATP into AMP was also inhibited by Ap 5 A. These results indicated that AMP arose from an ATP:AMP phosphotransferase activity and excluded the possibility of the hydrolysis of ADP into AMP by the tonoplast ATPase. AMP was degraded by the microsomal fraction from protoplasts or by the cytosol while the tonoplast vesicles did not hydrolyze it. This observation was used to assess the purity of tonoplasts.