Bisubstrate inhibitors represent a potentially powerful group of compounds that have found significant therapeutic utility. Although these compounds have been synthesized and tested against a number of enzymes that catalyze sequential bireactant reactions, the detailed theory for predicting the expected patterns of inhibition against the two substrates for various bireactant kinetic mechanisms has, heretofore, not been presented. We have derived the rate equations for all likely sequential bireactant mechanisms and provide two examples in which bisubstrate inhibitors allow the kinetic mechanism to be determined. Bisubstrate inhibitor kinetics is a powerful diagnostic for the determination of kinetic mechanisms.
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Biochemistry
January 2025
Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States.
1-Deoxy-d-xylulose 5-phosphate synthase (DXPS) is a unique thiamin diphosphate (ThDP)-dependent enzyme that catalyzes the formation of DXP, a branchpoint metabolite required for the biosynthesis of vitamins and isoprenoids in bacterial pathogens. DXPS has relaxed substrate specificity and utilizes a gated mechanism, equipping DXPS to sense and respond to diverse substrates. We speculate that pathogens utilize this distinct gated mechanism in different ways to support metabolic adaptation during infection.
View Article and Find Full Text PDFBioorg Med Chem Lett
November 2024
Department of Chemistry, University of Nebraska at Kearney, Kearney, NE 69949, USA. Electronic address:
Arylalkylamine N-acetyltransferase (AANAT) catalyzes the rate-limiting step in melatonin synthesis and is a potential target for disorders involving melatonin overproduction, such as seasonal affective disorder. Previously described AANAT inhibitor bromoacetyltryptamine (BAT) and benzothiophenes analogs were reported to react with CoASH to form potent bisubstrate inhibitors through AANAT's alkyltransferase function, which is secondary to its role as an acetyltransferase. We replaced the bromoacetyl group in BAT with various Michael acceptors to mitigate possible off-target activity of its bromoacetyl group.
View Article and Find Full Text PDFBioorg Med Chem Lett
November 2024
Center for Structural Biology, National Cancer Institute, Frederick, MD 21702, USA.
6-Hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK) is a key enzyme in the folate biosynthesis pathway. It catalyzes the pyrophosphoryl transfer from ATP to 6-hydroxymethyl-7,8-dihydropterin (HP). HPPK is essential for microorganisms but is absent in mammals.
View Article and Find Full Text PDFChembiochem
December 2024
Epigenetic Chemical Biology, Department of Structural Biology and Chemistry, Institut Pasteur, Université Paris Cité, CNRS UMR n°3523 Chem4Life, F-75015, Paris, France.
J Med Chem
September 2024
Pharmaceutical analysis Laboratory, College of Pharmacy, University of Manitoba, 750 McDermot Avenue West, Winnipeg, Manitoba R3E 0T5, Canada.
Protein arginine -methyltransferases (PRMT) are a family of -adenosyl-l-methionine (SAM)-dependent enzymes that transfer methyl-groups to the ω-N of arginyl residues in proteins. PRMTs are involved in regulating gene expression, RNA splicing, and other activities. PRMT1 is responsible for most cellular arginine methylation, and its dysregulation is involved in many cancers.
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