Biomaterial Database

Maturation, internalization, and turnover of soluble and membrane proteins associated with atrial myocyte secretory granules. 1993

J Y Maltese, and B A Eipper

Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.

Primary cultures of neonatal atrial myocytes were used to study the biosynthesis of a prominent secretory granule enzyme that occurs naturally in soluble and integral membrane forms. The two most prominent forms of peptidylglycine alpha-amidating monooxygenase PAM) in atrial myocytes are type I integral membrane proteins (PAM-1 and -2); smaller amounts of a soluble form, PAM-3, are also found. All three PAM proteins are N-glycosylated, and PAM-1 also has sialylated O-linked oligosaccharide. Two hours after their biosynthesis, approximately half of the newly synthesized PAM-1 and PAM-2 proteins have acquired N-linked oligosaccharide chains resistant to digestion with endoglycosidase-H. Secretion of newly synthesized PAM-3 is detectable within 90 min after biosynthesis and is largely complete within 4 h. Release of the catalytic domains of PAM-1 and PAM-2, which requires endoproteolytic cleavage, occurs at a slow rate for many hours after biosynthesis. Release of PAM-3 and the soluble PAM proteins derived from PAM-1 and PAM-2 can be stimulated by secretagogue. Integral membrane PAM proteins that reach the surface of atrial myocytes are internalized and enter the endocytic pathway. The turnover of newly synthesized PAM-1 and PAM-2 is only partially accounted for by the release of soluble PAM protein into the medium and may involve a significant contribution from intracellular degradation.

UI	MeSH Term	Description	Entries
D008715	Methionine	A sulfur-containing essential L-amino acid that is important in many body functions.	L-Methionine,Liquimeth,Methionine, L-Isomer,Pedameth,L-Isomer Methionine,Methionine, L Isomer
D009097	Multienzyme Complexes	Systems of enzymes which function sequentially by catalyzing consecutive reactions linked by common metabolic intermediates. They may involve simply a transfer of water molecules or hydrogen atoms and may be associated with large supramolecular structures such as MITOCHONDRIA or RIBOSOMES.	Complexes, Multienzyme
D009206	Myocardium	The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow.	Muscle, Cardiac,Muscle, Heart,Cardiac Muscle,Myocardia,Cardiac Muscles,Heart Muscle,Heart Muscles,Muscles, Cardiac,Muscles, Heart
D011233	Precipitin Tests	Serologic tests in which a positive reaction manifested by visible CHEMICAL PRECIPITATION occurs when a soluble ANTIGEN reacts with its precipitins, i.e., ANTIBODIES that can form a precipitate.	Precipitin Test,Test, Precipitin,Tests, Precipitin
D003470	Culture Media	Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.	Media, Culture
D003594	Cytoplasmic Granules	Condensed areas of cellular material that may be bounded by a membrane.	Cytoplasmic Granule,Granule, Cytoplasmic,Granules, Cytoplasmic
D006325	Heart Atria	The chambers of the heart, to which the BLOOD returns from the circulation.	Heart Atrium,Left Atrium,Right Atrium,Atria, Heart,Atrium, Heart,Atrium, Left,Atrium, Right
D006899	Mixed Function Oxygenases	Widely distributed enzymes that carry out oxidation-reduction reactions in which one atom of the oxygen molecule is incorporated into the organic substrate; the other oxygen atom is reduced and combined with hydrogen ions to form water. They are also known as monooxygenases or hydroxylases. These reactions require two substrates as reductants for each of the two oxygen atoms. There are different classes of monooxygenases depending on the type of hydrogen-providing cosubstrate (COENZYMES) required in the mixed-function oxidation.	Hydroxylase,Hydroxylases,Mixed Function Oxidase,Mixed Function Oxygenase,Monooxygenase,Monooxygenases,Mixed Function Oxidases,Function Oxidase, Mixed,Function Oxygenase, Mixed,Oxidase, Mixed Function,Oxidases, Mixed Function,Oxygenase, Mixed Function,Oxygenases, Mixed Function
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D000906	Antibodies	Immunoglobulin molecules having a specific amino acid sequence by virtue of which they interact only with the ANTIGEN (or a very similar shape) that induced their synthesis in cells of the lymphoid series (especially PLASMA CELLS).