Guanylate cyclase in olfactory cilia from rat and pig.
A guanylate cyclase was identified in cilia from rat and pig olfactory epithelia. Enzyme activities were 200-250 and 90-100 pmol/min.mg-1, respectively. Activity required the presence of non-ionic detergents, e.g., 0.1% Lubrol PX. MnGTP, not MgGTP was used as a substrate. Furthermore, 0.9 mM free Mn2+ was necessary for optimal activity indicating a regulatory site for a divalent cation. The guanylate cyclase displayed sigmoidal Michaelis-Menten kinetics suggesting cooperativity between MnGTP and enzyme. S0.5 was 160 microM MnGTP. The Hill coefficient of 1.7 indicates that more than one class of substrate-binding sites interact in a positive cooperative manner. ATP inhibited the enzyme and linearized plots of substrate kinetics with MnGTP. SH-Blocking agents reversibly inhibited enzyme activity. Sodium azide and nitroprusside were without effect as were several odorants. A guanylate cyclase activity in cilia from tracheal tissue had properties similar to the olfactory enzyme.
Steinlen
S
S
Pharmazeutisches Institut, University of Tübingen, F.R.G.
Klumpp
S
S
Schultz
J E
JE
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002923:Cilia / Q000201:enzymology; D005260:Female; D006160:Guanosine Triphosphate / Q000494:pharmacology; D006162:Guanylate Cyclase / Q000378:metabolism*; D007700:Kinetics; D009831:Olfactory Mucosa / Q000201:enzymology*; D000077423:Polidocanol; D011092:Polyethylene Glycols / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013552:Swine; D014132:Trachea / Q000201:enzymology
D000077423:Polidocanol; D011092:Polyethylene Glycols; C037047:manganese GTP; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D006162:Guanylate Cyclase