title: Failure of low temperature to arrest degradation of 14C-adenosine 5'-diphosphate by human plasma in the presence of EDTA.
abstract: Degradation of 14C-ADP in human platelet-rich and platelet-poor plasmas was studied. Three procedures were tested to determine which method was most effective in "stopping" enzyme reactions. One involved the immediate addition of perchloric acid to the reaction mixture at the end of the incubation period. Another involved "stopping" enzyme reactions at 0 degree C for about 20 min before the addition of perchloric acid. The third involved adding EDTA (10 mM final concentration) to "stop" the reactions at the end of incubation. The protein-free extracts from the plasmas were processed for adenine nucleotide assays by thin-layer chromatography. Addition of perchoric acid was most effective. Low temperature did not stop degradation of 14C-ADP in plasma even in the presence of EDTA. 14C-ADP was converted primarily to 14C-AMP. ADPase activity was the same in platelet-rich and platelet-poor plasmas. We conclude that the addition of EDTA and the cooling of plasma did not completely stop the enzymic degradation of ADP.
mesh_terms: D000244:Adenosine Diphosphate / Q000097:blood*; D003080:Cold Temperature; D004492:Edetic Acid / Q000494:pharmacology*; D006801:Humans; D008297:Male; D010744:Phosphoric Monoester Hydrolases / Q000037:antagonists & inhibitors* / Q000097:blood
chemical_list: D000244:Adenosine Diphosphate; D004492:Edetic Acid; D010744:Phosphoric Monoester Hydrolases