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Definition
 
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alpha-Crystallin A Chain definition: One of the subunits of alpha-crystallins. Unlike ALPHA-CRYSTALLIN B CHAIN the expression of ALPHA-CRYSTALLIN A CHAIN is limited primarily to the lens (LENS, CRYSTALLINE).
Glycoprotein Hormones, alpha Subunit definition: The alpha chain of pituitary glycoprotein hormones (THYROTROPIN; FOLLICLE STIMULATING HORMONE; LUTEINIZING HORMONE) and the placental CHORIONIC GONADOTROPIN. Within a species, the alpha subunits of these four hormones are identical; the distinct functional characteristics of these glycoprotein hormones are determined by the unique beta subunits. Both subunits, the non-covalently bound heterodimers, are required for full biologic activity.
Sigma Factor definition: A protein which is a subunit of RNA polymerase. It effects initiation of specific RNA chains from DNA.
Follicle Stimulating Hormone, beta Subunit definition: The beta subunit of follicle stimulating hormone. It is a 15-kDa glycopolypeptide. Full biological activity of FSH requires the non-covalently bound heterodimers of an alpha and a beta subunit. Mutation of the FSHB gene causes delayed puberty, or infertility.
Luteinizing Hormone, beta Subunit definition: The beta subunit of luteinizing hormone. It is a 15-kDa glycopolypeptide with structure similar to the beta subunit of the placental chorionic gonadatropin (CHORIONIC GONADOTROPIN, BETA SUBUNIT, HUMAN) except for the additional 31 amino acids at the C-terminal of CG-beta. Full biological activity of LH requires the non-covalently bound heterodimers of an alpha and a beta subunit. Mutation of the LHB gene causes HYPOGONADISM and infertility.
Thyrotropin, beta Subunit definition: The beta subunit of thyroid stimulating hormone, thyrotropin. It is a 112-amino acid glycopolypeptide of about 16 kD. Full biological activity of TSH requires the non-covalently bound heterodimers of an alpha and a beta subunit.
Integrin alpha1 definition: An integrin alpha subunit that binds COLLAGEN and LAMININ though its I domain. It combines with INTEGRIN BETA1 to form the heterodimer INTEGRIN ALPHA1BETA1.
alpha-Crystallin B Chain definition: One of the alpha crystallin subunits. In addition to being expressed in the lens (LENS, CRYSTALLINE), alpha-crystallin B chain has been found in a variety of tissues such as HEART; BRAIN; MUSCLE; and KIDNEY. Accumulation of the protein in the brain is associated with NEURODEGENERATIVE DISEASES such as CREUTZFELDT-JAKOB SYNDROME and ALEXANDER DISEASE.
Inhibin Beta A definition: The inhibin beta A subunit joins the alpha subunit to form a pituitary FSH secretion inhibitor. Inhibin has been shown to regulate gonadal stromal cell proliferation negatively and to have tumor-suppressor activity. In addition, serum levels of inhibin have been shown to reflect the size of granulosa-cell tumors and can therefore be used as a marker for primary as well as recurrent disease. Because expression in gonadal and various extragonadal tissues may vary severalfold in a tissue-specific fashion, it is proposed that inhibin may be both a growth/differentiation factor and a hormone. Furthermore, the beta A subunit forms a homodimer, activin A, and also joins with a beta B subunit to form a heterodimer, activin AB, both of which stimulate FSH secretion. (from LocusLink)
Protein Subunits definition: Single chains of amino acids that are the units of multimeric PROTEINS. Multimeric proteins can be composed of identical or non-identical subunits. One or more monomeric subunits may compose a protomer which itself is a subunit structure of a larger assembly.
Catalytic Domain definition: The region of an enzyme that interacts with its substrate to cause the enzymatic reaction.
GTP-Binding Protein alpha Subunits definition: The GTPase-containing subunits of heterotrimeric GTP-binding proteins. When dissociated from the heterotrimeric complex these subunits interact with a variety of second messenger systems. Hydrolysis of GTP by the inherent GTPase activity of the subunit causes it to revert to its inactive (heterotrimeric) form. The GTP-Binding protein alpha subunits are grouped into families according to the type of action they have on second messenger systems.
Vaccines, Subunit definition: Vaccines consisting of one or more antigens that stimulate a strong immune response. They are purified from microorganisms or produced by recombinant DNA techniques, or they can be chemically synthesized peptides.
Antigens, CD98 Heavy Chain definition: A transmembrane glycoprotein subunit that can dimerize with a variety of light chain subunits (ANTIGENS, CD98 LIGHT CHAINS). This protein subunit serves a diverse array of functions including amino acid transport and cell fusion. Its function is altered depending which of the light chain subunits it interacts with.
Interleukin-2 Receptor alpha Subunit definition: A low affinity interleukin-2 receptor subunit that combines with the INTERLEUKIN-2 RECEPTOR BETA SUBUNIT and the INTERLEUKIN RECEPTOR COMMON GAMMA-CHAIN to form a high affinity receptor for INTERLEUKIN-2.
Interleukin-2 Receptor Alpha Chain definition: The interleukin 2 (IL2) receptor alpha (IL2RA) and beta (IL2RB) chains, together with the common gamma chain (IL2RG), constitute the high-affinity IL2 receptor. Homodimeric alpha chains (IL2RA) result in low-affinity receptor, while homodimeric beta (IL2RB) chains produce a medium-affinity receptor. Normally an integral-membrane protein, soluble IL2RA has been isolated and determined to result from extracellular proteolysis. (LocusLink)
Interleukin-2 Receptor Alpha Chain definition: Interleukin-2 receptor alpha chain (272 aa, 31 kD) is a cell fate protein that is encoded by the human IL2RA gene and has roles in immune response, cell proliferation, apoptosis and signal transduction.
beta-Crystallin A Chain definition: The acidic subunit of beta-crystallins.
Immunoglobulin Subunits definition: The PROTEIN SUBUNITS of the multimeric IMMUNOGLOBULIN proteins, such as IGA; IGD; IGE; IGG; and IGM. Included are the heavy and light chains which contain the specific ANTIGEN binding domains, as well as the accessory proteins that are part of the the secreted forms of IGM and IGA; (SECRETORY IGA).
Interleukin-23 Subunit p19 definition: A subunit of interleukin-23. It combines with INTERLEUKIN-12 SUBUNIT P40, which is shared between the two cytokines, to form in the active interleukin-23 cytokine.
Ribosome Subunits, Large, Eukaryotic definition: The large subunit of the 80s ribosome of eukaryotes. It is composed of the 28S RIBOSOMAL RNA, the 5.8S RIBOSOMAL RNA, the 5S RIBOSOMAL RNA, and about 50 different RIBOSOMAL PROTEINS.
Interleukin-5 Receptor alpha Subunit definition: A low affinity interleukin-5 receptor subunit that combines with the CYTOKINE RECEPTOR COMMON BETA SUBUNIT to form a high affinity receptor for INTERLEUKIN-5. Several isoforms of the interleukin-5 receptor alpha subunit exist due to multiple ALTERNATIVE SPLICING.
Interleukin-5 Receptor Subunit Alpha definition: Interleukin-5 receptor subunit alpha (420 aa, 48 kD) is a cell division process protein that is encoded by the human IL5RA gene and has roles in cell proliferation and signal transduction.
Interleukin-3 Receptor alpha Subunit definition: A low affinity interleukin-3 receptor subunit that combines with the CYTOKINE RECEPTOR COMMON BETA SUBUNIT to form a high affinity receptor for INTERLEUKIN-3.
Subunit definition: A single unit of a multimeric object.
Interleukin-4 Receptor alpha Subunit definition: A receptor subunit that is a component of the TYPE I INTERLEUKIN-4 RECEPTOR and the TYPE II INTERLEUKIN-4 RECEPTOR. It signals through interaction of its cytoplasmic domain with JANUS KINASES such as JANUS KINASE 1.
Interleukin-11 Receptor alpha Subunit definition: A low affinity interleukin-11 receptor subunit that combines with the CYTOKINE RECEPTOR GP130 to form a high affinity receptor for INTERLEUKIN-11. Multiple isoforms of this protein exist due to ALTERNATIVE SPLICING of its MRNA.
Interleukin-15 Receptor alpha Subunit definition: A low affinity interleukin-15 receptor subunit that combines with the INTERLEUKIN-2 RECEPTOR BETA SUBUNIT and the INTERLEUKIN RECEPTOR COMMON GAMMA-CHAIN to form a high affinity receptor for INTERLEUKIN-15.
Ribosome Subunits, Small, Eukaryotic definition: The small subunit of the 80s ribosome of eukaryotes. It is composed of the 18S RIBOSOMAL RNA and 32 different RIBOSOMAL PROTEINS.
Ribosome Subunits definition: The two dissimilar sized ribonucleoprotein complexes that comprise a RIBOSOME - the large ribosomal subunit and the small ribosomal subunit. The eukaryotic 80S ribosome is composed of a 60S large subunit and a 40S small subunit. The bacterial 70S ribosome is composed of a 50S large subunit and a 30S small subunit.
ribosomal subunit definition: Either of the two ribonucleoprotein complexes that associate to form a ribosome. [GOC:mah]
Thyrotropin Alfa definition: A highly purified recombinant glycoprotein form of human THYROID-STIMULATING HORMONE, produced by recombinant DNA technology comprising two non-covalently linked subunits, an alpha subunit of 92 amino acid residues containing two N-linked glycosylation sites, and a beta subunit of 118 residues containing one N-linked glycosylation site. The amino acid sequence of thyrotropin alfa is identical to that of human pituitary thyroid stimulating hormone.