Overexpression of the recombinant enzyme in CHO cells greatly enhances expression of the endogenous gene, implicating a feedback mechanism on the alpha-AE gene.
Once a hormone is secreted by an endocrine tissue, it generally binds to a specific plasma protein carrier, with the complex being disseminated to distant tissues.Other receptors are composed of multiple polypeptides.For example, the insulin receptor is a disulfide-linked tetramer with the β-subunits spanning the membrane and the α-subunits located on the exterior surface.Nicholas Lorenzo, MD, MHA, CPE Founding Editor-in-Chief, e Medicine Neurology; Founder and CEO/CMO, PHLT Consultants; Chief Medical Officer, Me MD Inc Nicholas Lorenzo, MD, MHA, CPE is a member of the following medical societies: Alpha Omega Alpha, American Association for Physician Leadership, American Academy of Neurology Disclosure: Nothing to disclose.Francisco Talavera, Pharm D, Ph D Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference Disclosure: Received salary from Medscape for employment. Helmi L Lutsep, MD Professor and Vice Chair, Department of Neurology, Oregon Health and Science University School of Medicine; Associate Director, OHSU Stroke Center Helmi L Lutsep, MD is a member of the following medical societies: American Academy of Neurology, American Stroke Association Disclosure: Medscape Neurology Editorial Advisory Board for: Stroke Adjudication Committee, CREST2; Executive Committee for the NINDS-funded DEFUSE3 Trial; Physician Advisory Board for Coherex Medical; Stroke Advisory Group for Re Walk Robotics, Inc.The purified enzyme is partially glycosylated and the glycosylated and nonglycosylated forms of the enzyme were separated on a Con A-Sepharose column.
The kinetic constants for dansyl-Tyr--Val--Gly, dansyl-Tyr--Val--alpha-hydroxyglycine, ascorbate, and catechol were the same for both forms of alpha-AE.
In a separate but related system, exocrine tissues secrete their products into ducts and then to the outside of the body or to the intestinal tract.
Classically, endocrine hormones are considered to be derived from amino acids, peptides, or sterols and to act at sites distant from their tissue of origin.
Carriers for steroid and thyroid hormones allow these very hydrophobic substances to be present in the plasma at concentrations several hundred-fold greater than their solubility in water would permit.
Carriers for small, hydrophilic amino acid-derived hormones prevent their filtration through the renal glomerulus, greatly prolonging their circulating half-life.
However, the latter definition has begun to blur as it is found that some secreted substances act at a distance (classical endocrines), close to the cells that secrete them (paracrines), or directly on the cell that secreted them (autocrines).