Category: P

Stable elementary particles having the smallest known positive charge, found in the nuclei of all elements. The proton mass is less than that of a neutron. A proton is the nucleus of the light hydrogen atom, i.e., the hydrogen ion. A positively charged particle located in the nucleus of an atom electron. A particle in…

Medicines that stop the stomach’s acid pump. Examples are omeprazole (oh-MEH-prah-zol) (Prilosec) and lansoprazole (lan-SOH-prah-zol) (Prevacid). A drug that blocks gastric acid secretion; used to treat ulcers of the gastrointestinal tract and gastroesophageal reflux disease (GERD). A drug which suppresses the final stage of gastric acid secretion by the proton pump in the gastric mucosa.…

Integral membrane proteins that transport protons across a membrane against a concentration gradient. This transport is driven by hydrolysis of ATP by H(+)-transporting ATP synthase. An enzyme system within the gastric mucosa that secretes gastric acids. A key enzyme system in the parietal cells of the mucosal lining of the stomach: hydrogen ions are produced…

Pertaining to, characterized by, or promoting proteolysis. An enzyme that promotes proteolysis (= the splitting of proteins by hydrolysis of the peptide bonds with formation of smaller polypeptides). Cause splitting of proteins into smaller products during digestion. Hydrolysis of proteins into smaller compounds through the activity of enzymes. In the chemistry of enzymes, hastening the…

Glycoproteins which have a very high polysaccharide content. A family of molecules that are fundamental components of mucus and connective tissues. They are composed of sugars linked to polypeptides and are found in organs and tissues throughout the body.  

The process of moving proteins from one cellular compartment (including extracellular) to another by various sorting and transport mechanisms such as gated transport, protein translocation, and vesicular transport.  

The vitamin K-dependent cofactor of activated protein C. Together with protein C, it inhibits the action of factors VIIIa and Va. A deficiency in protein S can lead to recurrent venous and arterial thrombosis.  

A family of enzymes that catalyze the conversion of ATP and a protein to ADP and a phosphoprotein. Enzymes capable of phosphorylating (covalently bonding a phosphate group to) certain amino acid residues in specific proteins. Enzymes that phosphorylate other proteins; important are protein kinase A and protein kinase C. There are four major kinases (A,…

The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. Quaternary protein structure describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).