Biomaterial Database

Characterization of glycoprotein hormone free alpha-subunit from human pituitary and placenta extracts. 1986

R Chen, and E Barnea, and R Benveniste

Standard alpha-subunit dissociated from glycoprotein hormones differs from individual (free) alpha-subunit found in sera or in cell culture media; secreted free alpha-subunit is larger, more acidic and lacks the ability of recombining in vitro with standard hCG-beta. It is unclear whether the large free alpha-subunit is only a secretory product or whether it is also present in tissue. Herein were studied the molecular size, the isoelectric pH, and the recombining activity of free alpha-subunit obtained from pituitary and placenta extracts. Sephadex exclusion chromatography showed the presence of both a large and a small form, and a changing large/small free alpha-subunit ratio in the various extracts. Most of the large form obtained from placenta extracts electrofocused into two peaks of pI 4.8 and 5.1. The large form showed no recombining activity with standard hCG-beta while the small free alpha-subunit recombined as well as did standard hCG-alpha. The observation of three common characteristics (a larger size, a pI 4.8, and a lack of recombining activity) suggests a similarity between the large secreted form and a fraction of the free alpha-subunit in tissue.

UI	MeSH Term	Description	Entries
D007525	Isoelectric Focusing	Electrophoresis in which a pH gradient is established in a gel medium and proteins migrate until they reach the site (or focus) at which the pH is equal to their isoelectric point.	Electrofocusing,Focusing, Isoelectric
D008970	Molecular Weight	The sum of the weight of all the atoms in a molecule.	Molecular Weights,Weight, Molecular,Weights, Molecular
D010446	Peptide Fragments	Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.	Peptide Fragment,Fragment, Peptide,Fragments, Peptide
D010902	Pituitary Gland	A small, unpaired gland situated in the SELLA TURCICA. It is connected to the HYPOTHALAMUS by a short stalk which is called the INFUNDIBULUM.	Hypophysis,Hypothalamus, Infundibular,Infundibular Stalk,Infundibular Stem,Infundibulum (Hypophysis),Infundibulum, Hypophyseal,Pituitary Stalk,Hypophyseal Infundibulum,Hypophyseal Stalk,Hypophysis Cerebri,Infundibulum,Cerebri, Hypophysis,Cerebrus, Hypophysis,Gland, Pituitary,Glands, Pituitary,Hypophyseal Stalks,Hypophyses,Hypophysis Cerebrus,Infundibular Hypothalamus,Infundibular Stalks,Infundibulums,Pituitary Glands,Pituitary Stalks,Stalk, Hypophyseal,Stalk, Infundibular,Stalks, Hypophyseal,Stalks, Infundibular
D010908	Pituitary Hormones, Anterior	Hormones secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). Structurally, they include polypeptide, protein, and glycoprotein molecules.	Adenohypophyseal Hormones,Anterior Pituitary Hormones,Hormones, Adenohypophyseal,Hormones, Anterior Pituitary
D010924	Placental Extracts	Extracts prepared from placental tissue; they may contain specific but uncharacterized factors or proteins with specific activities.	Placental Extract,Extract, Placental,Extracts, Placental
D011247	Pregnancy	The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.	Gestation,Pregnancies
D011261	Pregnancy Trimester, First	The beginning third of a human PREGNANCY, from the first day of the last normal menstrual period (MENSTRUATION) through the completion of 14 weeks (98 days) of gestation.	Early Placental Phase,Pregnancy, First Trimester,Trimester, First,Early Placental Phases,First Pregnancy Trimester,First Pregnancy Trimesters,First Trimester,First Trimester Pregnancies,First Trimester Pregnancy,First Trimesters,Phase, Early Placental,Phases, Early Placental,Placental Phase, Early,Placental Phases, Early,Pregnancies, First Trimester,Pregnancy Trimesters, First,Trimesters, First
D011262	Pregnancy Trimester, Second	The middle third of a human PREGNANCY, from the beginning of the 15th through the 28th completed week (99 to 196 days) of gestation.	Midtrimester,Pregnancy, Second Trimester,Trimester, Second,Midtrimesters,Pregnancies, Second Trimester,Pregnancy Trimesters, Second,Second Pregnancy Trimester,Second Pregnancy Trimesters,Second Trimester,Second Trimester Pregnancies,Second Trimester Pregnancy,Second Trimesters,Trimesters, Second
D011863	Radioimmunoassay	Classic quantitative assay for detection of antigen-antibody reactions using a radioactively labeled substance (radioligand) either directly or indirectly to measure the binding of the unlabeled substance to a specific antibody or other receptor system. Non-immunogenic substances (e.g., haptens) can be measured if coupled to larger carrier proteins (e.g., bovine gamma-globulin or human serum albumin) capable of inducing antibody formation.	Radioimmunoassays