Labile disulfide bonds in human placental insulin receptor

Journal Article · Sun Dec 31 23:00:00 EST 1989 · Proceedings of the National Academy of Sciences of the United States of America; (USA)

DOI:https://doi.org/10.1073/pnas.87.1.419· OSTI ID:6897756

Finn, F M; Ridge, K D; Hofmann, K ^[1]

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1. Univ. of Pittsburgh School of Medicine, PA (USA)

The disulfide crosslinking pattern of human placental insulin receptor was investigated using selective reduction with tributylphosphine followed by alkylation with N-({sup 3}H)ethylmaleimide. Insulin receptor contains a single sulfhydryl group in each {beta} subunit whose alkylation with N-({sup 3}H)ethylmaleimide inhibits receptor autophosphorylation. Alkylation is partially inhibited by ATP or the nonhydrolyzable substrate analog adenosine 5{prime}-({beta},{gamma}-imido)triphosphate when the nucleotides are added as MN{sup 2+} complexes. Neither insulin nor 6 M guanidinium chloride renders additional sulfhydryl groups accessible to alkylation. When the receptor is reduced under drastic conditions with tributylphosphine in guanidinium chloride, 32 or the 37 sulfhydryl groups in the receptor's {alpha} subunit can be alkylated with N-({sup 3}H)ethylmaleimide. Surprisingly only three of the 10 cysteines in the {beta} subunit become titratable under identical conditions. By using highly selective reducing conditions, the authors were able to determine quantitatively the maximum number of disulfide bridges that link the two {alpha}{beta} halves to form the tetrameric structures and those that couple the {alpha} to the {beta} subunits. Liberation of two sulfhydryl groups in the {alpha} and one in the {beta} subunit resulted in formation of {alpha}{beta} dimers. Free {beta} subunit was formed when additional disulfide bond was reduced. Three models of the arrangement of the labile disulfide bonds, consistent with these findings, are proposed.

• OSTI ID: 6897756
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America; (USA), Journal Name: Proceedings of the National Academy of Sciences of the United States of America; (USA) Vol. 87:1; ISSN 0027-8424; ISSN PNASA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALBUMINS
ALKALI METAL COMPOUNDS
ALKYLATION
ANIMALS
ATP
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBON 14 COMPOUNDS
CATIONS
CHARGED PARTICLES
CHEMICAL BONDS
CHEMICAL REACTIONS
CROSS-LINKING
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
FETAL MEMBRANES
GLYCOPROTEINS
HALIDES
HALOGEN COMPOUNDS
HORMONES
HYDROGEN COMPOUNDS
IMIDES
INORGANIC PHOSPHORS
INSULIN
INTERMEDIATE MASS NUCLEI
IODIDES
IODINE 125
IODINE COMPOUNDS
IODINE ISOTOPES
IONS
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
LIGHT NUCLEI
MAMMALS
MAN
MANGANESE COMPOUNDS
MEMBRANE PROTEINS
MEMBRANES
MOLECULAR STRUCTURE
NUCLEI
NUCLEOTIDES
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PEPTIDE HORMONES
PHOSPHORS
PHOSPHORUS 32
PHOSPHORUS ISOTOPES
PHOSPHORYLATION
PLACENTA
POLYMERIZATION
PRIMATES
PROTEINS
RADIOISOTOPES
RADIORECEPTOR ASSAY
RECEPTORS
REDUCTION
SODIUM COMPOUNDS
SODIUM IODIDES
TRACER TECHNIQUES
TRANSITION ELEMENT COMPOUNDS
TRITIUM COMPOUNDS
VERTEBRATES