CYB561 ELISA Kits

Cytochrome b561 is a major transmembrane protein of catecholamine and neuropeptide secretory vesicles. Cytochrome b561 is an electron transfer protein unique to neuroendocrine secretory vesicles. was first discovered in catecholamine storage granules and was subsequently found to be specific to catecholamine and neuropeptide secretory vesicles of the adrenal medulla, pituitary gland, and other neuroendocrine tissues. This 30-kDa protein comprises 15% of the granule membrane protein and is present in both small synaptic vesicles and large dense core vesicles. Cytochrome b561 is a protein that in humans is encoded by the CYB561 gene Secretory vesicle-specific electron transport protein.

Plays a central role with ascorbic acid in the biosynthesis of several catecholamine and peptide neurotransmitters. Ascorbic acid serves as the extravesicular electron donor for cytochrome b561, and semidehydroascorbic acid acts as the intravesicular electron acceptor, which replenishes the high intravesicular ascorbic acid concentrations. Ascorbic acid serves as a cofactor for intravesicular dopamine _-hydroxylase activity in catecholamine storage granules and peptidyl _-amidating monooxygenase activity in neuropeptide storage vesicles. Appears to be a simple, functionally symmetric electron transfer protein and acts as a pure electron channel. Significant levels of cytochrome b561 mRNA expression were detected in colon cancer cell lines, T cell lymphomas, and undifferentiated cell lines such as K-562 compared to peripheral blood leukocytes. Cytochrome b561 plays a pivotal role in regenerating ascorbate in neuroendocrine vesicles for dopamine _-hydroxylase and peptidyl _-amidase, and, hence, understanding the regulation of cytochrome b561 may yield insights for development and neuroendocrine disorders. Constitutes 15% of the membrane protein in chromaffin granules, cytochrome b561 may have evolved concurrently with the formation of the vesicles.