Biomaterial Database

Reaction of human choriomammotropin with hydrogen peroxide. 1977

R A Houghten, and C H Li

Treatment of human choriomammotropin with hydrogen peroxide in the absence of denaturant was found to oxidize five of its six methionine residues to sulfoxide; the residue not oxidized was found to be methionine-170. This derivative was identical to the native hormone by exclusion chromatography, circular dichroism spectra, and rate of tryptic digestion, but suffered a very substantial drop in biological activity. In the presence of 8 M urea all of the methionines could be oxidized with hydrogen peroxide or alkylated with iodoacetic acid. The physical properties of these completely methionine-modified derivatives were significantly changed and biological activity had again been very substantially decreased. In control experiments, treatment of the native hormone with 8 M urea did not affect its physical, spectral or biological properties. Amino acid analysis of the derivatives was completely in accord with that expected.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008715	Methionine	A sulfur-containing essential L-amino acid that is important in many body functions.	L-Methionine,Liquimeth,Methionine, L-Isomer,Pedameth,L-Isomer Methionine,Methionine, L Isomer
D010446	Peptide Fragments	Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.	Peptide Fragment,Fragment, Peptide,Fragments, Peptide
D010928	Placental Lactogen	A polypeptide hormone of approximately 25 kDa that is produced by the SYNCYTIOTROPHOBLASTS of the PLACENTA, also known as chorionic somatomammotropin. It has both GROWTH HORMONE and PROLACTIN activities on growth, lactation, and luteal steroid production. In women, placental lactogen secretion begins soon after implantation and increases to 1 g or more a day in late pregnancy. Placental lactogen is also an insulin antagonist.	Choriomammotropin,Chorionic Somatomammotropin, Human,Human Placental Lactogen,Lactogen Hormone, Placental,Mammotropic Hormone, Placental,Somatomammotropin, Chorionic,Choriomammotrophin,HCS (Human Chorionic Somatomammotropin),HPL (Human Placental Lactogen),PAPP-D,Placental Luteotropin,Pregnancy-Associated Plasma Protein D,Chorionic Somatomammotropin,Human Chorionic Somatomammotropin,Lactogen, Placental,Luteotropin, Placental,Placental Lactogen, Human,Placental Mammotropic Hormone,Pregnancy Associated Plasma Protein D
D011487	Protein Conformation	The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).	Conformation, Protein,Conformations, Protein,Protein Conformations
D002942	Circular Dichroism	A change from planar to elliptic polarization when an initially plane-polarized light wave traverses an optically active medium. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Circular Dichroism, Vibrational,Dichroism, Circular,Vibrational Circular Dichroism
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D006861	Hydrogen Peroxide	A strong oxidizing agent used in aqueous solution as a ripening agent, bleach, and topical anti-infective. It is relatively unstable and solutions deteriorate over time unless stabilized by the addition of acetanilide or similar organic materials.	Hydrogen Peroxide (H2O2),Hydroperoxide,Oxydol,Perhydrol,Superoxol,Peroxide, Hydrogen
D000595	Amino Acid Sequence	The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.	Protein Structure, Primary,Amino Acid Sequences,Sequence, Amino Acid,Sequences, Amino Acid,Primary Protein Structure,Primary Protein Structures,Protein Structures, Primary,Structure, Primary Protein,Structures, Primary Protein
D000596	Amino Acids	Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.	Amino Acid,Acid, Amino,Acids, Amino