Streptosporangium sibiricum SibL catalyzes the methyl transfer from S-adenosylmethionine (SAM) to 3-hydroxykynurenine (3-HK) to produce S-adenosylhomocysteine (SAH) and 3-hydroxy-4-methyl-kynurenine for sibiromycin biosynthesis. Here, we present the crystal structures of apo-form Ss-SibL, Ss-SibL/SAH binary complex and Ss-SibL/SAH/3-HK ternary complex. Ss-SibL is a homodimer. Each subunit compr...

The purification of homogeneous glutathione S-transferases B and C from rat liver is described. Kinetic and physical properties of these enzymes are compared with those of homogeneous transferases A and E. The letter designations for the transferases are based on the reverse order of elution from carboxymethylcellulose, the purification step in which the transferases are separated from each oth...

The enzyme-substrate complex is inherently transient, rendering its detection difficult. In our framework designed for bisubstrate systems-isotope-labeled, activity-based identification and tracking (IsoLAIT)-the common substrate, such as S-adenosyl-l-methionine (AdoMet) for methyltransferases, is replaced by an analogue (e.g., S-adenosyl-l-vinthionine) that, as a probe, creates a tightly bound...

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aim :  to evaluate the association of dnmt1 and mgmt amino acid substitution polymorphisms and colorectal cancer in iranian population. background : the mgmt and dnmt1 are two important methyltransferase enzymes. amino acid substitution polymorphisms in mgmt and dnmt1 genes may be associated with the genetic susceptibility to sporadic colorectal cancer. patients and methods : we assessed eight ...

Cephalosporin antibiotics with structures that include the heterocyclic leaving group 1-methyltetrazole-5-thiol (MTT) can cause hypoprothrombinemia and hemorrhage as a result of MTT-dependent inhibition of the gamma-carboxylation of glutamate. The structure of cefazolin also includes a heterocyclic thiol, 2-methyl-1,3,4-thiadiazole-5-thiol (MTD), and this compound can also inhibit the gamma-car...

PURPOSE Thiopurine drugs are well established treatments in the management of inflammatory bowel disease (IBD), but their use is limited by significant adverse drug reactions (ADRs). Thiopurine S-methyltransferase (TPMT) is an important enzyme involved in thiopurine metabolism. Several clinical guidelines recommend determining TPMT genotype or phenotype before initiating thiopurine therapy. Alt...

Abbreviations: ALS: Amyotrophic Lateral Sclerosis; ATP: Adenosine Triphosphate; CBS: Cystathionine β-Synthase; CNS: Central Nervous System; COMT: Catechol-O-Methyl-Transferase; CYP2E1: Cytochrome P450 2E1; eNOS: Endothelial Nitric Oxide Synthase; Hcy: Homocysteine; L-DOPA: Levodopa; mPT: Mitochondrial Permeability Transition; MPTP: 1-Methyl 4-Phenyl 1,2,3,6-Tetrahydropyridine; MTHFR: Methylene ...

INTRODUCTION Thiopurine drugs are metabolized via S-methylation and catalyzed by thiopurine S-methyltransferase (TPMT). Patients with very low TPMT activity are at high risk of fatal bone marrow toxicity when standard doses of thiopurine drugs are administered. TPMT genotyping can predict TPMT activity and is not affected by transfusion or red blood cell defects. Here, we report a new allele-sp...