Detail of "37589-80-3"

Reference

GTP-binding regulatory protein sensitive to hormone

GTP-binding regulatory protein sensitive to hormone. Higashijima, Tsutomu; Miyazawa, Tatsuo (Fac. Sci., Tokyo Univ., Tokyo 113, Japan). Kagaku (Kyoto), 41(3), 196-7 (Japanese) 1986. CODEN: KAKYAU. ISSN: 0451-1964. DOCUMENT TYPE: Journal CA Section: 2 (Mammalian Hormones) Investigations on the rate-detg. step in the binding of GTP analogs to GTP-binding protein (G protein), on the conformational change of G protein by GTP analogs, and on the hydrolysis of GTP by G protein clarified the role of G protein in transmembrane control. The binding rate of water-insol. GTP analogs, i.e., GTPgS [37589-80-3] and GppNHp [34273-04-6], to the purified G protein was very low, but the rate was high in the presence of hormone-receptor complex. Kinetic anal. on the binding of GTPgS to G protein indicated that the dissocn. of GDP [146-91-8] from G protein was the rate-limiting step in the binding process of GTPgS to G protein. Namely, the hormone-receptor complex lowered the affinity of GDP toward the G protein and promoted the dissocn. of GDP from G protein. The fluorescent intensity of the tryptophan residue was increased in the a-subunit of the GDP-binding GO protein by the addn. of Mg2+ after the preincubation of GOa with GTPgS in absence of Mg2+, indicating that the transformation of the inactive to the active form of G protein was induced rapidly by Mg2+. The active form of G protein activated adenyl cyclase, and resulted in the prodn. of cAMP, which was stopped when the conformation of the G protein changed to the inactive form with the hydrolysis of GTP. The G protein will play a part in the transmembrane control, possibly by modulating responses initiated by an increase in the concn. of cAMP, which will be induced by the primary messengers such as hormones or neurotransmitters.

Lipid requirements for reconstitution of the delipidated b-adrenergic receptor and the regulatory protein

Lipid requirements for reconstitution of the delipidated b-adrenergic receptor and the regulatory protein. Kirilovsky, Jorge; Steiner-Mordoch, Sonia; Selinger, Zvi; Schramm, Michael (Inst. Life Sci., Hebrew Univ. Jerusalem, Jerusalem 91904, Israel). FEBS Lett., 183(1), 75-80 (English) 1985. CODEN: FEBLAL. ISSN: 0014-5793. DOCUMENT TYPE: Journal CA Section: 2 (Mammalian Hormones) Section cross-reference(s): 6 The role of lipids in the interaction of the b-adrenergic receptor (R) with the regulatory protein (Gs) was investigated. Solubilized prepns. of R and of G, from turkey erythrocytes were delipidated by gel filtration. They were subsequently combined and reconstituted by the addn. of various lipids. When reconstitution was carried out in the presence of soybean lipids, Gs could be fully activated via R by addn. of hormone plus GTPgS [37589-80-3]. Purified phospholipids or a phospholipid fraction from soybean failed to produce an active system. Fractionation of soybean lipids revealed that acetone-sol. neutral lipids are essential for the reconstitution of a hormone responsive system. The acetone fraction could be replaced by specific neutral lipids such as a-tocopherol [59-02-9] or cholesteryl arachidonate [604-34-2] while a mixt. of phosphatidylethanolamine, phosphatidylcholine, and phosphatidylserine satisfied the phospholipid requirement of the system.