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A second form of adenine phosphoribosyltransferase in Arabidopsis thaliana with relative specificity towards cytokinins
Author(s) -
Schnorr Kirk Matthew,
Gaillard Catherine,
Biget Elisabeth,
Nygaard Per,
Laloue Michel
Publication year - 1996
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.1996.9060891.x
Subject(s) - adenine phosphoribosyltransferase , intron , biology , complementation , arabidopsis thaliana , gene , mutant , microbiology and biotechnology , biochemistry , escherichia coli , genetics , enzyme , purine
Summary Adenine phosphoribosyltransferase (APRTase) is an important enzyme for its ability to convert adenine, a by‐product of many biochemical reactions, into AMP. By functional complementation of an Escherichia coli mutant, cDNAs encoding two APRTases have been cloned from Arabidopsis thaliana . One of the cDNAs ( ATapt1 )has been previously identified while the second ( ATapt2 ) is of a previously unknown type. Kinetic analysis of the two enzymes purified from E. coli expressing the two cDNAs indicates that ATapt2 has a higher affinity for cytokinin than the ATapt1. RNase protection studies indicate that the ATapt2 , is not expressed in leaves. Analysis of the gene structure indicates that ATapt2 has identical intron positions to ATapt1 , but neither the intron sequence nor intron size are conserved between the two genes. The implications of a second, differentially expressed APRTase with affinity for both adenine and cytokinin are discussed.