Effects of some modulators on purine nucleoside phosphorylase activity in myocardial tissue.
Purine nucleoside phosphorylase (PNP) in mammalian tissue is an enzyme responsible for formation of purine bases in DNA. It is also believed that PNP is crucial under energy-deprived conditions for the cell to metabolise adenosine during ATP degradation. This work describes a new method for determination of PNP activity in myocardial tissue using a commercially available substrate, 2-amino-6-mercapto-7-methylpurine riboside (MESG). The method involves the photometric assessment of the reaction between PNP (extracted from myocardial tissue) and MESG. Quantification as well as temperature- and pH-dependency for myocardial PNP activity is described. Also, the effect of some modulators has been studied. We have established the presence of PNP activity in pig myocardial tissue. Further, the results indicate a pH tolerance under slightly acid conditions and a calcium ion dependence of the enzyme.
Aberg
Anna-Maja
AM
Department of Surgical and Perioperative Sciences, Anesthesiology and Intensive Care Medicine, University Hospital of Umeå, Umeå, Sweden. annamaja.aberg@anestesi.umu.se
Ronquist
Gunnar
G
Haney
Michael
M
Waldenstrom
Anders
A
D000241:Adenosine / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D004492:Edetic Acid / Q000494:pharmacology; D006151:Guanosine / Q000031:analogs & derivatives / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D009206:Myocardium / Q000201:enzymology; D011683:Purine-Nucleoside Phosphorylase / Q000037:antagonists & inhibitors / Q000187:drug effects / Q000378:metabolism*; D019311:Staurosporine / Q000494:pharmacology; D013379:Substrate Specificity; D013552:Swine; D019284:Thapsigargin / Q000494:pharmacology; D013872:Thionucleosides / Q000378:metabolism
D013872:Thionucleosides; D006151:Guanosine; C074696:6-mercapto-7-methylguanosine; D019284:Thapsigargin; D004492:Edetic Acid; D011683:Purine-Nucleoside Phosphorylase; D019311:Staurosporine; D000241:Adenosine; D002118:Calcium