title: Guanylyl cyclase activity in rat brain myelin and white matter.
abstract: Purified myelin from rat brainstem was found to have an appreciable level of guanylyl cyclase activity, as seen in the formation of 3',5'-cyclic GMP from [3H]GTP at a rate approximately 45% that of whole brainstem. Freshly isolated myelin from pooled rat brainstems was incubated with GTP in an appropriate mixture. This gave rise to 29.9 +/- 3.6 pmol of 3',5'-cyclic GMP/mg of protein/min measured by HPLC and a similar result (26.7 +/- 2.6 pmol/mg/min) with 125I-3',5'-cyclic GMP radioimmunoassay. The latter method applied to the reaction product from whole brainstem gave a value of 56.6 +/- 3.4 pmol/mg/min. In analyzing brainstem products by HPLC we observed in most trials concurrent formation of a second radiolabeled product that comigrated with 2',3'-cyclic GMP but that, on further examination, proved not to be that product. Its identity remains unknown.
authors.affiliation: Department of Neurosciences, UMDNJ-New Jersey Medical School, Newark 07103.
authors.forename: G
authors.initials: G
authors.lastname: Chakraborty
authors.forename: R W
authors.initials: RW
authors.lastname: Ledeen
mesh_terms: D000818:Animals; D001933:Brain Stem / Q000201:enzymology*; D002851:Chromatography, High Pressure Liquid; D000242:Cyclic AMP / Q000032:analysis; D006150:Guanine Nucleotides / Q000302:isolation & purification / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D006162:Guanylate Cyclase / Q000378:metabolism*; D008297:Male; D009186:Myelin Sheath / Q000201:enzymology*; D011863:Radioimmunoassay; D051381:Rats; D017207:Rats, Sprague-Dawley; D014316:Tritium
chemical_list: D006150:Guanine Nucleotides; D014316:Tritium; D006160:Guanosine Triphosphate; D000242:Cyclic AMP; D006162:Guanylate Cyclase