Biomaterial Database

Isolation and amino acid sequence of COOH-terminal fragments from the beta subunit of human choriogonadotropin. 1977

S Birken, and R E Canfield

The amino acid sequence of the unique COOH-terminal region of the beta subunit of human choriogonadotropin has been reinvestigated. The desialylated subunit was digested with thermolysin and a 27-residue peptide from positions 115 through 141 isolated in a high yield. Quantitative Edman sequence degradation of this peptide, of another peptide produced by thermolysin digestion containing residues 142 to 145, and of two tryptic peptides (residues 123 to 145, 134 to 145) has established that the amino acid sequence of this region is: (formula: see text). In addition, the positions of attachment of the carbohydrate moieties to serine residues was established by a direct procedure using alkaline elimination and 35S-labeled sulfite addition, which yields [35S]-cysteic acid residues at the site of a substituted serine. Carbohydrate side chains in the COOH-terminal region have been shown to exist at residues 121, 127, 132, and 138. These studies have also resulted in the development of improved methods for the purification of COOH-terminal peptides of the human choriogonadotropin beta subunit.

UI	MeSH Term	Description	Entries
D010446	Peptide Fragments	Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.	Peptide Fragment,Fragment, Peptide,Fragments, Peptide
D006063	Chorionic Gonadotropin	A gonadotropic glycoprotein hormone produced primarily by the PLACENTA. Similar to the pituitary LUTEINIZING HORMONE in structure and function, chorionic gonadotropin is involved in maintaining the CORPUS LUTEUM during pregnancy. CG consists of two noncovalently linked subunits, alpha and beta. Within a species, the alpha subunit is virtually identical to the alpha subunits of the three pituitary glycoprotein hormones (TSH, LH, and FSH), but the beta subunit is unique and confers its biological specificity (CHORIONIC GONADOTROPIN, BETA SUBUNIT, HUMAN).	Chorionic Gonadotropin, Human,HCG (Human Chorionic Gonadotropin),Biogonadil,Choriogonadotropin,Choriogonin,Chorulon,Gonabion,Human Chorionic Gonadotropin,Pregnyl,Gonadotropin, Chorionic,Gonadotropin, Human Chorionic
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
D013820	Thermolysin	A thermostable extracellular metalloendopeptidase containing four calcium ions. (Enzyme Nomenclature, 1992) 3.4.24.27.	Thermolysin S
D046911	Macromolecular Substances	Compounds and molecular complexes that consist of very large numbers of atoms and are generally over 500 kDa in size. In biological systems macromolecular substances usually can be visualized using ELECTRON MICROSCOPY and are distinguished from ORGANELLES by the lack of a membrane structure.	Macromolecular Complexes,Macromolecular Compounds,Macromolecular Compounds and Complexes,Complexes, Macromolecular,Compounds, Macromolecular,Substances, Macromolecular