GPHA2 Human

Human thyrostimulin is a member of the glycoprotein hormone family, which are characterized by their structure of two subunits: a common alpha-subunit and a specific beta-subunit. These subunits combine non-covalently to form a functional heterodimer. In humans, the alpha-subunit interacts with four different beta-subunits, resulting in four distinct hormones: follicle-stimulating hormone (FSH), luteinizing hormone (LH), thyroid-stimulating hormone (TSH), and chorionic gonadotropin (CG). Produced primarily in the anterior pituitary, FSH, LH, and TSH are crucial for regulating the hypothalamus-pituitary axis, a key endocrine pathway. These hormones exert their effects by binding to specific G protein-coupled receptors located in their target organs: TSH receptors in the thyroid and LH and FSH receptors in the gonads. Glycoprotein hormones are found exclusively in vertebrates and exhibit a high degree of conservation across species, from primitive fish like Chondrostei to humans. This conservation is evident in both their amino acid sequences and functional characteristics. Corticotroph-derived glycoprotein hormone (CGH), also known as thyrostimulin, is composed of the glycoprotein hormone alpha 2 (GPHA2) and glycoprotein hormone beta 5 (GPHB5) subunits. Recombinant A2/B5 heterodimeric glycoproteins exhibit specific binding to human TSH receptors, with no interaction observed for LH or FSH receptors. This high affinity for TSH receptors has been confirmed through radioligand receptor assays. Furthermore, the heterodimer stimulates cAMP production and thymidine incorporation in cultured thyroid cells, indicating its biological activity. In vivo studies in TSH-suppressed rats have demonstrated its ability to elevate serum thyroxine levels. These findings collectively support the designation of this novel heterodimeric glycoprotein hormone as thyrostimulin, reflecting its primary function in thyroid stimulation. The presence of thyrostimulin in the anterior pituitary, a region known to express TSH receptors, suggests a potential paracrine mode of action.

Recombinant Human GPHA2, expressed in E. coli, is a single polypeptide chain devoid of glycosylation. It encompasses 120 amino acids, resulting in a molecular weight of 13.28 kDa. A His tag, comprising 14 additional amino acids, is incorporated into the recombinant protein. The amino acid sequence of recombinant human Thyrostimulin beta subunit exhibits complete homology (100%) with the corresponding human Thyrostimulin beta subunit sequence, excluding the signal sequence (N-terminal 24 amino acids). The purification of Thyrostimulin is achieved using proprietary chromatographic methods.

White powder, obtained through filtration and lyophilization (freeze-drying).

GPHA2 is subjected to filtration (0.4 μm) and subsequent lyophilization from a solution of 0.5 mg/ml in 0.05 M acetate buffer with a pH of 4.

To prepare a working stock solution of approximately 0.5 mg/ml, it is recommended to reconstitute the lyophilized pellet by adding 0.1 M acetate buffer (pH 4) and allowing for complete dissolution. For dilutions requiring a higher pH, intensive dilution with an appropriate buffer to a concentration of 10 μg/ml is advised. It is important to note that the solubility of this protein is limited at higher concentrations. Please be aware that this product is not sterile. Prior to use in cell culture, it is essential to filter the product using an appropriate sterile filter.

Lyophilized Thyrostimulin, while stable at room temperature for a duration of 3 weeks, should be stored in a desiccated state at a temperature below -18°C. Following reconstitution, GPHA2 should be stored at 4°C for a period of 2-7 days. For extended storage, it is recommended to store the reconstituted protein at a temperature below -18°C. The addition of a carrier protein (0.1% HSA or BSA) is advisable for long-term storage. It is important to avoid repeated freeze-thaw cycles.

The purity of the product exceeds 95.0%, as determined by the following analytical methods: (a) Reverse-phase high-performance liquid chromatography (RP-HPLC) (b) Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE)

GPA2, GPHA2, ZSIG51, Glycoprotein hormone alpha-2, MGC126572.

Escherichia Coli.

MRGSHHHHHH GMAS QEAVIPG CHLHPFNVTV RSDRQGTCQG SHVAQACVGH CESSAFPSRY SVLVASGYRH NITSVSQCCT ISGLKKVKVQ LQCVGSRREE LEIFTARACQCDMCRLSRY.