Phosphorylation of adenosine in renal brush-border membrane vesicles by an exchange reaction catalysed by adenosine kinase.
Uptake of [3H]adenosine in brush-border membrane (BBM) vesicles from either rat or pig kidney leads to an accumulation of intravesicular [3H]AMP. The lack of significant levels of ATP and the presence of AMP in BBM indicated that a phosphotransfer between [3H]adenosine and AMP occurs. The phosphotransfer activity is inhibited by iodotubercidin, which suggests that it is performed by adenosine kinase acting in an ATP-independent manner. The existence of a similar phosphotransferase activity was demonstrated in membrane-free extracts from pig kidney. From the compounds tested it was shown that a variety of mononucleotides could act as phosphate donors. The results suggest that phosphotransfer reactions may be physiologically relevant in kidney.
Sayós
J
J
Departament de Bioquímica i Fisiologia, Facultat de Química, Universitat de Barcelona, Catalunya, Spain.
Solsona
C
C
Mallol
J
J
Lluis
C
C
Franco
R
R
D000227:Adenine Nucleotides / Q000096:biosynthesis / Q000378:metabolism; D000241:Adenosine / Q000378:metabolism*; D000248:Adenosine Kinase / Q000378:metabolism*; D000818:Animals; D002384:Catalysis; D066298:In Vitro Techniques; D007687:Kidney Tubules, Proximal / Q000378:metabolism*; D008297:Male; D008871:Microvilli / Q000378:metabolism; D010766:Phosphorylation; D051381:Rats; D017208:Rats, Wistar; D013552:Swine
D000227:Adenine Nucleotides; D000248:Adenosine Kinase; D000241:Adenosine