Tissue, pathway, proteinase, peptidase, protease ,acrosin, lipoprotein, activator, caspase, trypsin, papain, esterase inhibitors are proteins or receptor ligands or receptor antagonists that bind to an enzyme receptor and decreases its activity. Since blocking an enzyme's activity can kill a pathogen or correct a metabolic imbalance, many drugs are enzyme inhibitors. Not all receptor antagonist that bind to enzymes are inhibitors; enzyme activator ligands or agonists bind to enzymes and increase their enzymatic activity, while enzyme substrates bind and are converted to products in the normal catalytic cycle of the enzyme.Associated membrane protein types are lipopolysaccharide selective barriers. Biological membranes include cell membranes, outer coverings of cells or organelles that allow passage of certain proteins and nuclear membranes, which cover a cell nucleus; and tissue membranes, such as mucosae and serosae.
