| amino acids, peptides, and proteins | Amino acids and chains of amino acids connected by peptide linkages. (12 Dec 1998) |
|---|---|
| second signaling system | <psychology> Pavlovian term for speech in which words are considered to be the second signals capable of producing conditioned responses. (05 Mar 2000) |
| hydrophilic signaling molecule | <molecular biology> A type of molecule which, because it is easily dissolved in water (it is hydrophilic), can easily move through cell membranes and thus can be secreted from one cell and move into a target cell where it triggers a particular event. Many hormones and growth factors are hydrophilic signaling molecules. (09 Oct 1997) |
| bitter peptides | Peptides that have a bitter taste and may spoil certain foods; often contain high proportions of leucyl, valyl, and aromatic amino acid residues. (05 Mar 2000) |
| peptides | Any member of a class of compounds of low molecular weight which yield two or more amino acids on hydrolysis. Formed by loss of water from the nh2 and cooh groups of adjacent amino acids, they are known as di-, tri-, tetra- (etc.) peptides, depending on the number of amino acids in the molecule. Peptides form the constituent parts of proteins. (12 Dec 1998) |
| signal peptides | Additional polypeptide sequence of 25 to 30 residues at the amino-terminal or carboxy-terminal end of proteins. The signal sequence signals the cellular fate or destination of a newly synthesised protein directing it to its ultimate destination in the cell. These leaders are recognised by the signal recognition particle and bound by specific receptor sites on the outer surface of the endoplasmic reticulum. They are then transported into the cisterna of the endoplasmic reticulum and from there directed to their ultimate destination in the cell. In prokaryotes, the signal peptides attach to the plasma membrane. These signal sequences are ultimately removed by specific peptidases. (12 Dec 1998) |
| opioid peptides | The endogenous peptides with opiate-like activity. The three major classes currently recognised are the enkephalins, the dynorphins, and the endorphins. Each of these families derives from different precursors, proenkephalin, prodynorphin, and pro-opiomelanocortin, respectively. There are also at least three classes of opioid receptors, but the peptide families do not map to the receptors in a simple way. (12 Dec 1998) |
| intercellular | Between cells: can be used either in the sense of connections between cells (as in intercellular junctions) or as an antonym for intra cellular. (18 Nov 1997) |
| intercellular adhesion molecule | See: ICAM. (18 Nov 1997) |
| intercellular adhesion molecule-1 | <chemical> A cell-surface ligand with a role in leukocyte adhesion and inflammation. Its production is induced by gamma-interferon and it is required for neutrophil migration into inflamed tissue. Chemical name: Glycoprotein ICAM 1 (human clone pHRVr1 deblocked protein moiety reduced) (12 Dec 1998) |
| intercellular bridges | Slender cytoplasmic strands connecting adjacent cells; in histological sections of the epidermis and other stratified squamous epithelia, the bridge's are processes attached by a desmosome and are shrinkage artifacts of fixation; true bridge's with cytoplasmic confluence exist between incompletely divided germ cells. Synonym: cell bridges, cytoplasmic bridges. (05 Mar 2000) |
| intercellular canaliculus | One of the fine channels between adjoining secretory cells, such as those between serous cells in salivary glands. (05 Mar 2000) |
| intercellular cement | A hypothetical adhesive substance formerly believed to occur between some epithelial cells. (05 Mar 2000) |
| intercellular digestion | Digestion in a cavity by means of secretions from the surrounding cells, such as occurs in the metazoa. (05 Mar 2000) |
| intercellular junctions | Direct contact of a cell with a neighboring cell. most such junctions are too small to be resolved by light microscopy, but they can be visualised by conventional or freeze-fracture electron microscopy, both of which show that the interacting cell membrane and often the underlying cytoplasm and the intervening extracellular space are highly specialised in these regions. (12 Dec 1998) |