A capillary electrophoretic assay for acetyl coenzyme A carboxylase

Insights into the methodology of acetyl-CoA carboxylase inhibition

Acetyl-CoA carboxylase catalyzes the first committed and regulated step in fatty acid synthesis in all animals, plants and bacteria. In most Gram-positive and Gram-negative bacteria, the enzyme is composed of three proteins: biotin carboxylase, biotin carboxyl carrier protein and carboxyltransferase. The reaction consists of two half-reactions. The first half reaction is catalyzed by biotin carboxylase and involves the carboxylation of the vitamin biotin which is covalently attached to the biotin carboxyl carrier protein. The second half reaction catalyzed by carboxyltransferase involves the transfer of the carboxyl group from biotin to acetyl-CoA to form malonyl-CoA. This chapter will describe the inhibitors of both the biotin carboxylase and carboxyltransferase components of bacterial acetyl-CoA carboxylase. Inhibitors that were used in the elucidation of the structure and mechanism of the enzyme will be discussed first. The second half will focus on inhibitors that also possess antibacterial activity.

The substance basis of Poria ameliorates hypothyroidism other than hyperthyroidism based on proteomics and metabolomics

Integrated metabolomics and proteomics analysis was carried out to study the effects of Poria and its split components (volatile oil, triterpenoid, oligosaccharide, amino acid, and crude polysaccharide) on rats of normal physiological model, hyperthyroidism model, and hypothyroidism model to explore the substance basis of Poria for hypothyroidism from the perspective of a holistic view in substance and energy metalism. The key pathways regulating substance and energy metabolism were screened, encompassing tricarboxylic acid cycle pathway, glycolysis/ gluconeogenesis pathways, biosynthesis of amino acid pathway, fatty acid biosynthesis pathway, pentose phosphate pathway, peroxisome proliferator-activated receptors pathway, etc Poria and its split components showed promoting effects on substance and energy metabolism in normal model, while showed amelioration effects on hypothyroidism model at different degrees, and had no significant improvement effects on hyperthyroidism in rats. Volatile oil, triterpenoid, and crude polysaccharide from Poria were regarded as substance basis of Poria ameliorating hypothyroidism other than hyperthyroidism. This work also revealed the feasibility of metabolomics and proteomics analysis to elucidate the effective substance basis of traditional Chinese medicine from a new viewpoint based on its effects on substance and energy metabolism.

Application of Capillary Electrophoresis with Laser-Induced Fluorescence to Immunoassays and Enzyme Assays

Capillary electrophoresis using laser-induced fluorescence detection (CE-LIF) is one of the most sensitive separation tools among electrical separation methods. The use of CE-LIF in immunoassays and enzyme assays has gained a reputation in recent years for its high detection sensitivity, short analysis time, and accurate quantification. Immunoassays are bioassay platforms that rely on binding reactions between an antigen (analyte) and a specific antibody. Enzyme assays measure enzymatic activity through quantitative analysis of substrates and products by the reaction of enzymes in purified enzyme or cell systems. These two category analyses play an important role in the context of biopharmaceutical analysis, clinical therapy, drug discovery, and diagnosis analysis. This review discusses the expanding portfolio of immune and enzyme assays using CE-LIF and focuses on the advantages and disadvantages of these methods over the ten years of existing technology since 2008.

Capillary electrophoretic assay of human acetyl-coenzyme A carboxylase 2

Human acetyl-coenzyme A carboxylase 2 catalyzes the carboxylation of acetyl coenzyme A to form malonyl coenzyme A, along with the conversion of magnesium-adenosine triphosphate complex to magnesium-adenosine diphosphate complex. A simple off-column capillary electrophoresis assay for human acetyl-coenzyme A carboxylase 2 was developed based on the separation of magnesium-adenosine triphosphate complex, magnesium-adenosine diphosphate complex, acetyl coenzyme A and malonyl coenzyme A with detection by ultraviolet absorption at 256 nm. When Mg²⁺ was absent from the separation buffer, the zones due to magnesium-adenosine triphosphate complex and magnesium-adenosine diphosphate complex both split and migrated as two separate peaks. With Mg²⁺ added to the separation buffer, magnesium-adenosine triphosphate complex and magnesium-adenosine diphosphate complex produced single peaks, and the reproducibility of peak shape and area improved for human acetyl-coenzyme A carboxylase 2 assay components. The final separation buffer used was 30.0 mM HEPES, 3.0 mM MgCl₂ , 2.5 mM KHCO₃ , and 2.5 mM potassium citrate at pH 7.50. The same buffer was used for the enzyme-catalyzed reaction (off-column). Inhibition of human acetyl-coenzyme A carboxylase 2 by CP-640186, a known inhibitor, was detected using the capillary electrophoresis assay.

An online immobilized α-glucosidase microreactor for enzyme kinetics and inhibition assays

A novel online α-glucosidase-immobilized microreactor was developed by immobilizing α-glucosidase on capillary inner wall. The microreactor combination with capillary electrophoresis was applied in studying enzyme kinetics and inhibition kinetics.

Capillary electrophoresis-based assay of phosphofructokinase-1

An assay was developed for phosphofructokinase-1 (PFK-1) using capillary electrophoresis (CE). In the glycolytic pathway, this enzyme catalyzes the rate-limiting step from fructose-6-phosphate and magnesium-bound adenosine triphosphate (Mg-ATP) to fructose-1,6-bisphosphate and magnesium-bound adenosine diphosphate (Mg-ADP). This enzyme has recently become a research target because of the importance of glycolysis in cancer and obesity. The CE assay for PFK-1 is based on the separation and detection by ultraviolet (UV) absorbance at 260 nm of Mg-ATP and Mg-ADP. The separation was enhanced by the addition of Mg²⁺ to the separation buffer. Inhibition studies of PFK-1 by aurintricarboxylic acid and palmitoyl coenzyme A were also performed. An IC₅₀ value was determined for aurintricarboxylic acid, and this value matched values in the literature obtained using coupled spectrophotometric assays. This assay for PFK-1 directly monitors the enzyme-catalyzed reaction, and the CE separation reduces the potential of spectral interference by inhibitors.