Identification and partial purification of an endogenous inhibitor of soluble guanylyl cyclase from bovine lung.
An endogenous inhibitor of soluble guanylyl cyclase from bovine lung has been partially purified by use of anion exchange, hydrophobic interaction, and gel filtration chromatography. This inhibitor is a protein with a molecular weight of about 149,000 which was estimated from its elution behavior, versus that of a series of standards, on a Sephacryl S-300-HR column. Its activity was measured by comparison of the level of cGMP production from soluble guanylyl cyclase in the presence and absence of the inhibitor protein. Soluble guanylyl cyclase is inhibited by this protein when either Mg2+ or Mn2+ is used as a cofactor. The insensitivity of its inhibitory activity to both isobutylmethylxanthine and the presence of cGMP demonstrates that this new protein is not a phosphodiesterase. This new protein inhibits both activated and unactivated soluble guanylyl cyclase. Because the inhibition was found to be noncompetitive with respect to the substrate, GTP, it appears that this inhibitor may be an allosteric regulator of soluble guanylyl cyclase.
Kim
T D
TD
Department of Chemistry, University of Wisconsin-Madison 53706.
Burstyn
J N
JN
D015106:3',5'-Cyclic-GMP Phosphodiesterases / Q000378:metabolism; D000818:Animals; D001685:Biological Factors / Q000302:isolation & purification* / Q000494:pharmacology; D002417:Cattle; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D000242:Cyclic AMP / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000302:isolation & purification* / Q000494:pharmacology; D006162:Guanylate Cyclase / Q000037:antagonists & inhibitors* / Q000302:isolation & purification; D007700:Kinetics; D008168:Lung / Q000201:enzymology / Q000378:metabolism*; D008970:Molecular Weight; D014357:Trypsin
D001685:Biological Factors; D004791:Enzyme Inhibitors; D000242:Cyclic AMP; D015106:3',5'-Cyclic-GMP Phosphodiesterases; D014357:Trypsin; D006162:Guanylate Cyclase