Reduction and reoxidation of equine gonadotropin alpha-subunits

dc.contributor.authorBousfield, George R.en_US
dc.contributor.authorWard, Darrell N.en_US
dc.descriptionClick on the DOI link below to access the article (may not be free).en_US
dc.description.abstractOvine (o) and equine (e) LH alpha-subunits were reduced and reoxidized using conditions known to be effective for bovine and human alpha-subunits. The major product of oLH alpha refolding was alpha-subunit monomer. In contrast, eLH alpha formed a 121,000 mol wt aggregate. Monomeric eLH alpha was recovered, but in greatly reduced yield. To test the effects of carbohydrate variation on the aggregation of equine alpha-subunits, all of the equine gonadotropin alpha-subunits (eFSH alpha, eCG alpha, eLH alpha, and free alpha-subunit) were reduced and reoxidized. In each case, the major product was the 121,000 mol wt aggregate accompanied by monomeric equine alpha. Removal of carbohydrate by trifluoromethane sulfonic acid hydrolysis accentuated the tendency to aggregation during reoxidation. Most reduced-reoxidized deglycosylated eLH alpha did not enter a 12% sodium dodecyl sulfate-polyacrylamide gel. The highest LH receptor-binding activities were found in the alpha-subunit preparations, eLH alpha itself and pituitary free alpha-subunit. Operationally, the latter was separated from eLH in the last step of the eLH purification procedure; thus, LH contamination in this preparation is likely. Reduction and reoxidation reduced the LH receptor-binding activity of these two preparations to the level of LH activity observed in the eFSH alpha and eCG alpha preparations. We concluded that the majority of the LH receptor-binding activity observed in equine alpha-subunit preparations was due to contamination with eLH. We also obtained preliminary evidence that the amino-terminal and carboxy-terminal fragments of proteolytically "nicked" equine alpha-subunits refolded properly to form alpha monomer.en_US
dc.description.versionpeer revieweden_US
dc.identifier.citationEndocrinology. 1992 Dec; 131(6): 2986-98.en_US
dc.publisherThe Endocrine Societyen_US
dc.subjectComparative Studyen_US
dc.subject.meshElectrophoresis, Polyacrylamide Gelen_US
dc.subject.meshFollicle Stimulating Hormone/chemistryen_US
dc.subject.meshFollicle Stimulating Hormone, beta Subuniten_US
dc.subject.meshGlycoprotein Hormones, alpha Subunit/chemistryen_US
dc.subject.meshMacromolecular Substancesen_US
dc.subject.meshPeptide Fragments/chemistryen_US
dc.subject.meshPituitary Gland/chemistryen_US
dc.subject.meshProtein Conformationen_US
dc.subject.meshReceptors, LH/metabolismen_US
dc.subject.meshFollicle Stimulating Hormone/metabolismen_US
dc.subject.meshGlycoprotein Hormones, alpha Subunit/metabolismen_US
dc.subject.meshPeptide Fragments/metabolismen_US
dc.titleReduction and reoxidation of equine gonadotropin alpha-subunitsen_US