Enzymes are proteins, or occasionally RNA, found in cells that act as biological catalysts. Their mode of action is to lower the activation energy of the reaction by forming an enzyme-substrate complex, which is a more stable intermediate than would be formed, were the enzyme not present. The...
There are several classes of Gprotein-linked receptor (Fig. 7.3c). The best known are seven-passmembrane proteins, meaning that they are composed of a singlepolypeptide chaincrossing the membrane seven times. These are associated with trimericG proteinscomposed of α, β and γ subunits. When ...
The term “allosteric” is of Greek origin, the root word “allos” meaning “other.” Thus, an allosteric site is a unique region of an enzyme other than the substrate binding site that leads to catalysis. At the allosteric site, the enzyme is regulated by noncovalent interaction with ...
γ-Secretase is an aspartyl intramembrane protease that cleaves the amyloid precursor protein (APP) involved in Alzheimer’s disease pathology and other transmembrane proteins. Substrate-bound structures reveal a stable hybrid β-sheet immediately follow
The ubiquitin-conjugating enzyme HR6B is required for spermatogenesis in mouse. Loss of HR6B results in aberrant histone modification patterns on the trancriptionally silenced X and Y chromosomes (XY body) and on centromeric chromatin in meiotic prophase
Wood A, Krogan NJ, Dover J, Schneider J, Heidt J, Boateng MA, Dean K, Golshani A, Zhang Y, Greenblatt JF, Johnston M, Shilatifard A: Bre1, an e3 ubiquitin ligase required for recruitment and substrate selection of rad6 at a promoter. Mol Cell. 2003, 11 (1): 267-274. 10.1016/...
(Molecular, Cellular, and Developmental Biology) medium were each spiked with 400 μM L-glutamine and compared against non-spiked controls. The values for the non-spiked media did not show any intrinsic variation when compared to water, indicating that there was no L-glutamine present in the...
Higher reaction temperatures associated with thermostable cellulases during the hydrolytic process may radically reduce substrate viscosity leading to higher reaction velocities and better substrate conversion at lower energy consumption [10–12]. To improve the cellulase mixture of T. reesei in its ...
coli by histidine); (2) substrate induction of enzyme synthesis (e.g., the induction of the synthesis of the first enzyme involved in cysteine biosynthesis in E. coli by the product of its reaction); (3) metabolite depression of enzyme synthesis (e.g., the synthesis of all amino acid ...
and the ability to be readily removed from the reaction mixture. As a consequence, an immobilized enzyme is bound to an inert, organic, inorganic, orinsoluble substancelikecalcium alginateorsilica. Connecting an enzyme to a solid substrate can also help it withstand environmental changes like in ...