Formycin triphosphate as a probe for the ATP binding site involved in the activation of guanylate cyclase.
Formycin A triphosphate (FTP), a fluorescent analog of ATP, slightly increased basal guanylate cyclase activity, but significantly potentiated guanylate cyclase activity stimulated by atrial natriuretic factor (ANF) in rat lung membranes. FTP potentiated ANF-stimulated guanylate cyclase activity with an EC50 at about 90 microM and inhibited ATP-stimulated guanylate cyclase activity with an IC50 at about 100 microM. These results indicate that FTP binds more tightly than ATP for the same binding site. Therefore, FTP would be an excellent tool for studying the ATP binding site.
Department of Medicine, Case Western Reserve University, Cleveland, OH 44106.
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D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000494:pharmacology; D001665:Binding Sites; D004789:Enzyme Activation; D005456:Fluorescent Dyes / Q000737:chemistry / Q000378:metabolism*; D005573:Formycins / Q000737:chemistry / Q000378:metabolism*; D006162:Guanylate Cyclase / Q000378:metabolism*; D008168:Lung / Q000201:enzymology / Q000378:metabolism; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012265:Ribonucleotides / Q000737:chemistry / Q000378:metabolism*
D005456:Fluorescent Dyes; D005573:Formycins; D012265:Ribonucleotides; C032552:formycin triphosphate; D009320:Atrial Natriuretic Factor; D000255:Adenosine Triphosphate; D006162:Guanylate Cyclase