Comparative studies on animal and plant apyrases (ATP diphosphohydrolase EC 3.6.1.5) with application of immunological techniques and various ATPase inhibitors.
Apyrase activity has been found in tissue of all investigated plant species. Seedlings soluble fractions accounted for 45-75% of the cell apyrase activity, whereas the apyrases isolated from microsomes accounted for 0.2-7% of the total homogenate activity. The ratio of the rate of ATP hydrolysis to the rate of ADP hydrolysis, Ksh, divides the apyrases into two groups: of Ksh > 1 (enzymes from most of monocot plants and bovine tissues) and of Ksh < 1 (enzymes from dicot plants). Triflupromazine strongly decreased the activity of wheat and bovine apyrases (first group) and does not inhibit the activity of the enzyme from potato (second group). Analysed apyrases reveal a significant antigenic diversity. Antibodies developed against soluble potato apyrase have no affinity to apyrase from microsomes of wheat seedlings. Immunological analysis confirmed that ATPase and ADPase activities of potato apyrase were associated with one protein. Apyrases, including animal ones, are insensitive to ATPases inhibitors and reagents of SH groups, whereas sodium deoxycholate inhibits all of the studied enzymes. NaF decreases activity plant enzymes, whereas erythrosine B and NaN3 only decreases bovine apyrases.
Komoszyński
M A
MA
Department of Biochemistry, Nicolaus Copernicus University, Toruń, Poland. michkom@ss.10.cc.uni.torun.pl
D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors; D000818:Animals; D001011:Aorta / Q000201:enzymology; D001081:Apyrase / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism*; D015153:Blotting, Western; D001921:Brain / Q000201:enzymology; D002417:Cattle; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D007700:Kinetics; D008861:Microsomes / Q000201:enzymology*; D010944:Plants / Q000201:enzymology*; D013045:Species Specificity
D004791:Enzyme Inhibitors; D000251:Adenosine Triphosphatases; D001081:Apyrase