| peptide chain initiation | The process whereby the formation of a peptide chain is started. This process requires (1) the 30s subunit, (2) the mRNA coding for the polypeptide to be made, (3) met-trnai, (4) initiation factors, and (5) GTP. (12 Dec 1998) |
|---|---|
| peptide initiation factors | Protein factors uniquely required during the initiation phase of protein synthesis. (12 Dec 1998) |
| peptide chain elongation | The process whereby an amino acid is joined through a substituted amide linkage to a chain of peptides. (12 Dec 1998) |
| peptide chain termination | The process whereby the last amino acid is added to a polypeptide. This termination is signaled by one of three termination triplets in the mRNA, immediately following the last amino acid codon. (12 Dec 1998) |
| post-translational modification | The enzymatic processing of a polypeptide chain after translation from messenger RNA and after peptide bond formation has occurred. Examples include glycosylation, acylation, limited proteolysis, phosphorylation, isoprenylation. (10 Oct 1997) |
| protein processing, post-translational | Any of various enzymically catalyzed post-translational modifications of peptides or proteins in the cell of origin. These modifications include carboxylation, hydroxylation, acetylation, phosphorylation, methylation, glycosylation, oxidation-reduction, degradation and lysis, peptide bond formation, and changes in molecular weight and electrophoretic motility. (12 Dec 1998) |
| translational control | <molecular biology> The control of protein synthesis by regulation of the translation step, for example by selective usage of preformed mRNA or instability of the mRNA. (18 Nov 1997) |
| translational repressor | A molecule that blocks translation by binding to a messenger RNA. (09 Oct 1997) |
| chain, orthodontic chain | <dentistry> A stretchable plastic chain used to hold archwires into brackets and to moke teeth. (08 Jan 1998) |
| initiation | 1. The first stage of tumour induction by a carcinogen; subtle alteration of cells by exposure to a carcinogenic agent so that they are likely to form a tumour upon subsequent exposure to a promoting agent (promotion). 2. Starting point of replication or translation in macromolecule biosynthesis. 3. Start of chemical or enzymatic reaction. (05 Mar 2000) |
| initiation codon | The codon 5' AUG in mRNA, at which polypeptide synthesis is started. It is recognised by formylmethionyl tRNA in bacteria and by methionyl tRNA in eukaryotes. (18 Nov 1997) |
| initiation complex | Complex between mRNA, 30S ribosomal subunit and formyl methionyl tRNA that requires GTP and initiation factors to function. (18 Nov 1997) |
| initiation factor | One of several soluble proteins involved in the initiation of protein or RNA synthesis. (05 Mar 2000) |
| initiation factors | The set of catalytic proteins required, in addition to mRNA and ribosomes, for protein synthesis to begin. In bacteria three distinct proteins have been identified: if 1 (8 kD), IF 2 (75 kD) and IF 3 (30 kD). at least 6-8 proteins have been identified in eukaryotes. IFs 1 and 2 enhance the binding of initiator tRNA to the initiation complex. (18 Nov 1997) |
| initiation tRNA | TRNA in prokaryotes containing a formyl-methionyl residue that initiates translation. Synonym: formyl-methionyl-tRNA, starter tRNA. (05 Mar 2000) |