Group transferases

IV. Dinuclear Metal Systems for Group Transferases and Their Models... 

Protein kinases and phosphatases play vital roles in intracellular signaling pathways and in the integration and control of major cellular processes. Kinases and other phosphoryl group transferases are essential in the metabolism of lipids, nucleotides, and other small biomolecules. The use of SBDD methods on such targets has expanded as more of their X-ray structures have been solved, and will continue to grow as more targets are validated for their involvement in human diseases. 

Biotransformation of xenobiotics takes place in two phases. In phase I (= functionalization reactions), reactive groups are either activated or inserted into the substance molecule, thus providing the lipophilic molecule with a functional hydrophilic group. (In phase II, a hydrophilic residue is added to this group transferases hereby catalyze the conjugation with an endogenous substance.) Phase I elfects the insertion of reactive (polar) groups (such as -OH, -COOH, -SH, -NH2) by means of four chemical processes oxidation, reduction, hydrolysis, and hydration. 

Kinases are enzymes that transfer a phosphate group from adenosine triphosphate (ATP), or other trinucleotide, to a number of biological substrates, such as sugars or proteins. They are part of a larger family of enzymes known as group transferases, but are limited to phosphate transfers. A typical reaction catalyzed by a kinase (e.g., hexokinase) is the phosphorylation of glucose upon its entry into a cell... 

This broad class of enzymes also includes dehydratases and many synthases. Dehydratases remove the elements of water from two adjacent carbon-carbon bonds to form a double bond. Certain enzymes in this group, such as certain group transferases, are commonly called synthases when the physiologically important direction of the reaction favors the formation of a carbon-carbon bond (e.g., citrate synthase). 

D) Clinical resistance mainly occurs through plasmid-mediated formation of group transferase enzymes... 

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