Detail of "68528-80-3"

Reference

Covalent cross-linking of vasoactive intestinal polypeptide to its receptors on intact human lymphoblasts

Covalent cross-linking of vasoactive intestinal polypeptide to its receptors on intact human lymphoblasts. Wood, Catherine L.; O'Dorisio, M. Sue (Coll. Med., Ohio State Univ., Columbus, OH 43210, USA). J. Biol. Chem., 260(2), 1243-7 (English) 1985. CODEN: JBCHA3. ISSN: 0021-9258. DOCUMENT TYPE: Journal CA Section: 2 (Mammalian Hormones) Section cross-reference(s): 6 125I-labeled VIP [37221-79-7] was covalently crosslinked with its binding sites on intact cultured human lymphoblasts by each of 3 bifunctional reagents: disuccinimidyl suberate [68528-80-3], ethylene glycol bis(succinimidyl succinate) [82540-27-0], and N-succinimidyl 6-(4'-azido-2'-nitrophenylamino)hexanoate [64309-05-3]. A 4th crosslinking agent with a shorter chain length, N-hydroxysuccinimidyl 4-azidobenzoate [53053-08-0], was much less effective in crosslinking 125I-VIP to the site. Anal. by SDS-polyacrylamide gel electrophoresis and autoradiog. demonstrated a band of mol. wt. (Mr) ~50,000, regardless of which crosslinker was used. The labeling of this band was specific in that it was prevented by 10-6M unlabeled VIP and was partially blocked by the homologous hormones secretin [1393-25-5] and glucagon [9007-92-5]. The relative potencies of these peptides in blocking the cross-linking of 125I-VIP to the Mr ~50,000 band of the lymphoblasts (VIP > secretin 3 glucagon) were similar to those previously found for competitive inhibition of 125I-VIP binding to its putative high-affinity receptor on these cells. The covalent crosslinking required a bifunctional reagent and it was dependent on both the no. of Molt cells and the concn. of 125I-VIP. The apparent mol. wt. of the crosslinked species was unchanged by treatment with dithiothreitol. Apparently, the Mr = 50,000 species represents 125I-VIP crosslinked to a specific plasma membrane receptor and the receptor does not contain interchain disulfide bonds.

Affinity labeling of the thyrotropin receptor

Affinity labeling of the thyrotropin receptor. Buckland, Paul R.; Creagh, Fionuala; Smith, Bernard Rees (Dep. Med., Welsh Natl. Sch. Med., Cardiff CF4 4XN, UK). Methodol. Surv. Biochem. Anal., 13(Invest. Membr.-Located Recept.), 277-93 (English) 1984. CODEN: MSBADU. ISSN: 0748-6715. DOCUMENT TYPE: Journal CA Section: 2 (Mammalian Hormones) Thyrotropin (TSH) [9002-71-5] receptors from different species and tissues were covalently cross-linked to 125I-labeled TSH, and the mol. wts. of the TSH-TSH receptor complexes elucidated. Two successful methods of cross-linking entail use of disuccinimidyl suberate (DSS) [68528-80-3] and N-hydroxysuccinimidyl-4-azidobenzoate (HSAB) [53053-08-0]. Highly purified bovine TSH (70 units/mg) was coupled to HSAB (which is photoreactive), labeled with 125I, then incubated with several different TSH receptor prepns. and coupled to the receptor by photolysis. Alternatively, the TSH was labeled with 125I and incubated with solubilized receptors; DSS effected the cross-linking. The TSH-TSH receptor complexes were analyzed by SDS-polyacrylamide gel electrophoresis with and without redn. by mercaptoethanol and autoradiog. Porcine, human and guinea pig thyroid TSH receptors and guinea pig fat-cell TSH receptors contain 2 subunits linked by 31 disulfide bridges; the mol. wts. are: porcine, 45 and 27 kilodaltons; human, 50 and 32; guinea pig thyroid, 60 and 31; and fat cell, 57 and 32.