Deciphering the SAM- and metal-dependent mechanism of O-methyltransferases in cystargolide and belactosin

Wolfgang Kuttenlochner1, Patrick Beller2, Leonard Kaysser3

  • 1Department of Bioscience, Center for Protein Assemblies (CPA), TUM School of Natural Sciences, Technical University of Munich, Garching, Germany.

Related Concept Videos

Drug Metabolism: Phase II Reactions01:14

Drug Metabolism: Phase II Reactions

Phase II reactions are essential for the detoxification and elimination of drugs from the body. These reactions involve the conjugation of parent drugs or their phase I metabolites with endogenous molecules, resulting in more hydrophilic drug conjugates. The primary conjugation reactions in this phase are sulfation and glucuronidation. Both sulfation and glucuronidation typically produce biologically inactive metabolites. However, in some cases involving prodrugs, active metabolites may be...
3.7K
Phase II Reactions: Methylation Reactions01:17

Phase II Reactions: Methylation Reactions

Methylation is a phase II biotransformation process involving the attachment of a methyl group to a substrate. Enzymes known as methyltransferases orchestrate this reaction.
The mechanism of methylation unfolds in two stages. The first stage sees a methyltransferase enzyme facilitating the transfer of a methyl group from S-adenosylmethionine (SAM) to the substrate, forming S-adenosylhomocysteine (SAH). The second stage involves further metabolism of SAH into homocysteine, which can be recycled...
170
Phase II Reactions: Sulfation and Conjugation with α-Amino Acids01:19

Phase II Reactions: Sulfation and Conjugation with α-Amino Acids

Sulfation and α-amino acid conjugation are two critical biotransformation reactions in drug metabolism. Sulfation, a phase II biotransformation reaction, involves adding a polar sulfate group to a drug, enhancing its water solubility and promoting excretion. This process can either co-occur with or occur independently of glucuronidation. Nonmicrosomal sulfotransferase enzymes catalyze the process. The reaction involves 3'-phosphoadenosine-5'-phosphosulfate or PAPS coenzyme...
199
Oligosaccharide Assembly01:24

Oligosaccharide Assembly

Protein glycosylation starts in the ER lumen and continues in the Golgi apparatus. Glycosyltransferases catalyze the addition of sugar molecules or glycosylation of proteins. Usually, these enzymes add sugars to the hydroxyl groups of selected serine or threonine residues to form O-linked glycans or the amino groups of asparagine residues to form N-linked glycans. Different positions on the same polypeptide chain can contain differently linked glycans.
Multiple sugar molecules that may or may...
2.8K
Phase I Reactions: Oxidation of Aliphatic and Aromatic Carbon-Containing Systems01:19

Phase I Reactions: Oxidation of Aliphatic and Aromatic Carbon-Containing Systems

Phase I biotransformation reactions are integral to drug metabolism, predominantly involving oxidative, reductive, and hydrolytic transformations. Chief among these are oxidative reactions, which enhance the hydrophilicity of xenobiotics and introduce polar functional groups to facilitate their elimination from the body.
Oxidation reactions are fundamental in aromatic carbon-containing systems. An example is the hydroxylation of phenobarbital, a process that transforms it into...
163
Ligand Binding and Linkage00:49

Ligand Binding and Linkage

Allosteric proteins have more than one ligand binding site; the binding of a ligand to any of these sites influences the binding of ligands to the other sites. When a protein is allosteric, its binding sites are called coupled or linked.  In the case of enzymes, the site that binds to the substrate is known as the active site and the other site is known as the regulatory site. When a ligand binds to the regulatory site, this leads to conformational changes in the protein that can influence...
4.8K