Effects of phospholipase A and triton x-100 on guanylate cyclase activity in mammary gland homogenates from mice.
The effects of a variety of agents on guanylate cyclase activity were tested in broken cell preparations of mammary glands from midpregnant mice. Of the agents tested, only phospholipase A, triton X-100, and an impure egg lysolecithin preparation enhanced the activity of guanylate cyclase in mammary gland homogenates; other agents, including sodium azide and phospholipase C, and purified egg lysolecithin had no effect. Phospholipase A increased the activity of guanylate cyclase in the 150,000 g pellet fractions of mammary gland homogenates, bud did not consistently enhance guanylate cyclase in the 150,000 g supernatant fractions. Phospholipase A did not appear to enhance guanylate cyclase activity by solublizing the enzyme from the 150,000 g pellet. Triton X-100, in contrast, appeared to act by solubilizing guanylate cyclase from the material present in the 150,000 g pellet. Triton X-100 increased by several fold guanylate cyclase activity in the tissue homogenates and the 150,000 g pellets, but did not consistently enhance enzyme activity in the 150,000 g supernatant. Triton X-100 had no effect on the apparent Km of guanylate cyclase.
D000818:Animals; D005260:Female; D006162:Guanylate Cyclase / Q000378:metabolism*; D008244:Lysophosphatidylcholines / Q000494:pharmacology; D008321:Mammary Glands, Animal / Q000201:enzymology*; D051379:Mice; D010740:Phospholipases / Q000494:pharmacology*; D011092:Polyethylene Glycols / Q000494:pharmacology*; D011247:Pregnancy; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology*
D008244:Lysophosphatidylcholines; D000644:Quaternary Ammonium Compounds; D011092:Polyethylene Glycols; D010740:Phospholipases; D006162:Guanylate Cyclase