In this study an effective method was developed to assay erythromycin ethylsuccinate for an oral suspension dosage form. The chromatographic separation was achieved on an X-Terra™ C18 analytical column. A mixture of acetonitrile–ammonium dihydrogen phosphate buffer (0.025 mol L-1) (60:40, V/V) ...

The solid-liquid equilibrium data of erythromycin ethylsuccinate in six pure organic solvents including tetrahydrofuran, acetone, acetonitrile, hexane, ethanol and 2-propanol were determined by using the gravimetric method over the temperature range from 288.15 K to 323.15 K. The experimental so...

Fatty acyl-Coenzyme A species (acyl-CoAs) are key biomarkers in studies focusing on cellular energy metabolism. Existing analytical approaches are unable to simultaneously detect the full range of short-, medium-, and long-chain acyl-CoAs, while chromatographic limitations encountered in the ana...

Zonal elution and high-performance affinity chromatography were used to examine interactions of the drugs digitoxin and acetyldigitoxin with the protein human serum albumin (HSA). This was done by injecting small amounts of digitoxin and acetyldigitoxin onto an immobilized HSA column in the pres...

Sisters aged 3 and 4 1/2 years, respectively, who had grown and developed normally were found to have methylmalonic aciduria. The elder had had only one previous illness, at 18 months, and was thriving at six years without treatment; she was excreting up to 2 gm methylmalonic acid per day. The y...

Certain amino acids and other compounds are metabolized via propionyl-CoA d-methylmalonyl-CoAl-methylmalonyl-CoAsuccinyl-CoA ↔ tricarboxylic acid cycle. d-Methylmalonyl-CoA can also be converted to methylmalonic acid and coenzyme A by a specific hydrolase that does not act on l-methylmalonyl-CoA...

Methylmalonyl coenzyme A (CoA) mutase has been purified to apparent homogeneity from human liver by a procedure involving column chromatography on DEAE-cellulose, Matrex-Gel Blue A, hydroxylapatite, and Sephadex G-150. The overall purification achieved is 500- to 600-fold, yield 3–5%. Electroph...

Publisher SummaryThis chapter discusses the preparation and purification of methylmalonyl coenzyme A. Two methods have been reported for the preparation of the monothioester of CoA and methylmalonate, including the mixed anhydride method and the reaction catalyzed by propionyl CoA carboxylase. T...

A rapid and high-yield synthesis of methylmalonyl coenzyme A is reported. The two-step procedure involves preparation of the thiophenyl ester of methylmalonic acid using dicyclohexylcarbodiimide as a condensing agent, followed by transesterification with coenzyme A, to yield methylmalonyl coenzy...

Methylmalonyl-coenzyme A mutase (MCM) is a 5′-deoxyadenosylcobalamin-linked mitochondrial enzyme that catalyzes the isomerization of L-methylmalonyl-coenzyme A to succinyl-coenzyme A. In vitro assays of total and holo-MCM activities are important tools for investigating the cobalamin pathway. S...

Background: The enzyme methylmalonyl-coenzyme A (CoA) mutase, an αβ heterodimer of 150 kDa, is a member of a class of enzymes that uses coenzyme B12 (adenosylcobalamin) as a cofactor. The enzyme induces the formation of an adenosyl radical from the cofactor. This radical then initiates a free-...

The reported presence of a coenzyme B12-dependent methylmalonyl-CoA mutase in potatoes has been reexamined. The enzyme converting methylmalonyl-CoA was purified to electrophoretic homogeneity. Examination of the reaction product by 1H, 31P NMR and mass spectrometry revealed that it was methylmal...

Methylmalonyl-coenzyme A (CoA) mutase, methylmalonyl-CoA decarboxylase and NADP+-isocitrate dehydrogenase activity profiles were determined in Saccharopolyspora erythraea CA340, an erythromycin producer, grown in glucose or ammonium chloride. Results show that methylmalonyl-CoA mutase and isocit...

Propionic acidemia (PA) is an inherited metabolic disease caused by low activity of propionyl coenzyme A (CoA) carboxylase (PCC), which metabolizes propionyl-CoA into methylmalonyl-CoA. Although many patients with PA have been identified by tandem mass spectrometry since the test was first inclu...

A simple HPLC method was developed to quantify rabbit plasma tetrandrine (Tet) with propranolol (Pro) as internal standard. Based on the established method Tet and Pro were eluted at 7.1 and 12.0 min, respectively. It was shown that the concentration-time data of Tet fit the classical two-compar...

The effects of tetrandrine, a Ca2+ antagonist of bis-benzylisoquinoline alkaloid origin, on endothelium-dependent and -independent vascular responsiveness were investigated in perfused rat mesenteric artery. In endothelium-intact preparations pre-contracted with 3 μM phenylephrine and fully rel...

Tetrandrine is a bisbenzylisoquinoline alkaloid derived from the root of a Chinese herbal medicine Stephania tetrandra S. Moore, which has been used traditionally for the treatment of hepatofibrogenic disease in China for several decades. In the present study, the inhibitory effects of tetrandri...

Tetrandrine, a bisbenylisoquinoline alkaloid isolated from the dried root of Stephenia tetrandra (S Moore), possesses a remarkable pharmacological profile. However, the mechanisms of tetrandrine hepatotoxicity remain to be elucidated. In this study, we first proved apoptosis and mitochondrial dy...

The ionic mechanism of tetrandrine, an alkaloid extracted from the Chinese medicinal herb Radix stephania tetrandrae, was investigated in A7r5 vascular smooth muscle cells. The nystatin-perforated whole-cell voltage-clamp technique was performed to examine the effects of tetrandrine on ionic cur...

Tetrandrine, a bis-benzylisoquinoline alkaloid from the root of Stephania tetrandra, induces apoptosis in human T-cell lines, lung carcinoma and hepatoblastoma cells. However, the mechanisms by which tetrandrine inhibits tumor cell growth are poorly understood. The purpose of the present study w...