A second form of adenine phosphoribosyltransferase in Arabidopsis thaliana with relative specificity towards cytokinins

被引:41
作者
Schnorr, KM
Gaillard, C
Biget, E
Nygaard, P
Laloue, M
机构
[1] INRA,BIOL CELLULAIRE LAB,ROUTE ST CYR,F-78026 VERSAILLES,FRANCE
[2] UNIV COPENHAGEN,DEPT BIOL CHEM,DK-1307 COPENHAGEN,DENMARK
关键词
D O I
10.1046/j.1365-313X.1996.9060891.x
中图分类号
Q94 [植物学];
学科分类号
071001 ;
摘要
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 (ATap2) 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.
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页码:891 / 898
页数:8
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