at Related Biological Terms

A pathway for anaerobic metabolism of sulphide by bacteria, e.g. in marine sediments; thiosulphate (S2O32-) is an intermediate between sulphide (S2-) and sulphate (SO42-) in reduction to the former, oxidation to the latter and disproportionation to both. Jorgensen, B.B. (1990) Science 249, 152-154

A non-ribosomal, non-RNA-dependent mechanism for the synthesis of bacterial cyclic oligopeptide antibiotics (e.g. gramicidin S) in which the amino acid residues are first transferred from amino acid adenylates to thiol groups of a peptide synthetase that then collects the residues, in sequence, on a phosphopantetheine arm until the mature peptide is cleaved off by a cyclizing transpeptidation reaction.

A graphical representation of the protonic dissociation of a compound, e.g. pH against equivalents of alkali added to the acid form of the compound.

A class of transmembrane transporters that includes the cystic fibrosis transmembrane regulator (CFTR) and transporters responsible for multidrug resistance. Transport is coupled to ATP hydrolysis but not to the counter- or co-transport of any other metabolite.

The substitution of one amino compound for another in an amide linkage, e.g. the cross-linking of fibrin by the displacement of NH3 from glutamine residues by an -amino group of a lysine residue to form an isopeptide bond.

The concurrent amination and reduction of a carbonyl of one compound as another is deaminated and oxidized; especially the conversion of one -amino acid into its corresponding -oxo acid as another -oxo acid is converted into its corresponding -amino acid, mediated by the pyridoxal phosphate prosthetic group of a transaminase (aminotransferase). (see also quinimine form)

The immediate use of mRNA transcripts for protein synthesis before the synthesis of the mRNA is complete; occurs in bacteria where RNA processing does not occur.

A transcriptional activator is a protein (transcription factor) that increases the transcription of a gene or set of genes. Activators are considered to have positive control over gene expression, as they function to promote gene transcription and, in some cases, are required for the transcription of genes to occur. Transcriptional activators are required to turn on the expression of genes in a eukaryotic cell. The transcriptional activation activity of the variant was evaluated through methods of the relative activity of luciferase. And the transcriptional activators of the two splicing variants are detected with a luciferase reporter in transient transfections of human embryonic kidney 293T cells. The yeast transcriptional activator GAL4, like many sequence-specific DNA-binding proteins, binds to DNA as a symmetrical dimer. The dimerization element of GAL4 is a segment of approximately 50 amino acids containing the heptad repeat characteristic of a coiled coil.

The substitution of one alcohol for another in an ester bond, e.g. the displacement of one 3'-hydroxy group of a phosphodiester bond by the 3'-hydroxy group of another nucleotide during the self-splicing of an RNA molecule, or the inteRNAl transfer of phosphate from a 3'-hydroxy to a 2'-hydroxy group during the reaction of pancreatic ribonuclease.

The process by which a cell LINE, that can normally be expected to undergo a limited number of cell divisions before death, becomes immortal; also the process by which isolated foreign DNA is introduced into a cell or bacterium.