Separation of pantothenic acid derivatives as precursors for the biosynthesis of the acetylation coenzyme by chromatography on DEAE-dellulose

The possibility of the chromatographic separation of pantothenic acid derivatives — 4-phosphopantothenate, pantethine, 4-phosphopantetheine, dephospho-CoA and CoA — on a column of DEAE-cellulose (DE-11 or Servacel DEAE 23 SH) has been studied, with their detection by radiometric, enzymatic, or spectrophotometric methods. The affinity of pantothenic acid and that of pantotheine for the ion-exchange resins used are identical. The phosphorylated derivatives of these compounds, which are eluted at higher values of a concentration gradient of lithium chloride, also have identical chromatographic characteristics. The separation of dephospho-CoA and CoA is not achieved on the chromatographic system investigated, but the elution of the fractions to free them from the retained nucleotide-containing precursors of the coenzyme can be used effectively for analytical purposes.Institute of Biochemistry, Academy of Sciences of the Belorussian SSR, Grodno. Translated from Khimiya Prirodnykh soedinenii, No. 2, pp. 258–262, March–April, 1987.     

Iterative algorithm of determining the stability of an equation of oscillations with damping

A problem of studying parametric oscillations with damping is reduced to a spectral problem for a linear bundle of operators in a Hilbert space. This spectral problem is solved by an efficient algorithm. The boundaries of the first stability domain for different values of a damping factor and a special form of a periodic function in the equation are calculated.     

Acyl group carriers. XVII. Synthesis of analogues of 3′-dephosphocoenzyme A with modified pyrophosphate groups

The synthesis has been performed of dephosphocoenzyme A, 4′,4″-di-0-(2′,3′-9-isopropylideneadenosineuronyl)pantethine, and of 4′,4″-di(2′,3′-isopropylideneadenosineuronylamino)-4′,4″-dideoxypantethine from 2′,3′-0-isopropylidene adenosineuronic acid, using as condensing agents the tert-butyl dicarbonatepyridine and the N,N′-dicyclohexylcarbodiimide-N-hydroxysuccinimide systems, respectively.     

Study of the transformations of 2-C-(indol-3-yl)methyl-α-l-xylo-hex-3-ulofuranosonic acid (the open form of ascorbigen) in an acidic medium

Transformation of ascorbigen in an acidic medium, which affects the carbohydrate moiety of the molecule and results in the formation of 2-hydroxy-4-hydroxymethyl-3-(indol-3-yl)cyclopent-2-enone, 5-hydroxymethyl-2-(indol-3-yl)methylidenetetrahydrofuran-3-one, and 2-(indol-3-yl)acetylfuran, was investigated. Isolation and identification of the intermediates allowed the elucidation of the mechanism of this domino-type reaction.     

Kinetics of the formation of pantolactone from pantothenates and its quantitative determination

The conditions of hydrolysis and lactonization of the calcium and sodium salts of pantothenic and pantoic acids have been studied. The selected conditions of hydrolysis (t=80°C, C_HCl=13%) led to a 100% yield of -alanine and pantothenates after 60 min from the beginning of hydrolysis, while the formation of pantolactone was complete in 105 min for the calcium salt and in 75 min for the sodium salt. The hydrolysis and lactonization reactions have been performed under the conditions mentioned, and the GLC of the pantolactone formed has permitted the determination of various concentrations of calcium pantothenate. The results obtained from the GLC analysis of pantolactone indicate the possibility of a quantitative determination of salts of pantothenic and pantoic acids. The sensitivity of this method is 0.2–5 nmole.Department of Metabolic Regulation, Academy of Sciences of the Belorussian SSR, Grodno. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 93–95, January–February, 1984.     

Investigations in the field of acyl group carriers. XVI. hydrolytic stability and enzymatic dephosphorylation of d-pantothenic acid 4′-phosphate

Samples of D-pantothenic acid .4-phosphate (I) have been investigated by IR spectroscopy in dimethyl sulfoxide and deuterated water and in the form of a thin film without a solvent.The vibrations of the carbonyl and amide groupings in (I) as compared with pantothenic acid (II) are found at higher frequencies in all media, which indicate the greater strength of these bonds. It is assumed that the resistance of (I) to hydrolysis as compared with (II) is due to the inclusion of the phosphate in a macrocycle by the formation of hydrogen bonds between the phosphate, hydroxy, amide, and carboxy groups of the molecule. The complete dephosphorylation of (I) has been achieved in concentrations of 0.0075 and 0.005 mM with the aid of a dialyzed preparation of orthophosphate monoester phosphohydrolase (E.C. 3.1.3.1).     

The precession of a parametric oscillation pendulum with Cardan suspension

The precession of a pendulum with a Cardan suspension point oscillating under an external periodic force is investigated. The parameters of precession versus the pendulum geometric characteristics and the external force frequency are studied both theoretically and numerically.