Rats malnourished since birth and fed a protein-free diet for 2 wk showed almost undetectable levels of liver microsomal aryl hydrocarbon (benzo[a]pyrene) hydroxylase. Treatment with benzo[a]pyrene rapidly enhanced this activity to levels higher than those observed with untreated normal rats. The carbon-monoxide-reduced cytochrome P-450 spectral peak was shifted from 452 nm in malnourished untreated rats to 448 nm in malnourished benzo[a]pyrene-injected rats and resulted in increases in the intensity of several microsomal protein bands (MW range 46,000-60,000) separated by gel electrophoresis. Malnourished rats then fed with a protein diet exhibited an important increase in aryl hydrocarbon hydroxylase activity, an increase in the intensity of microsomal protein electrophoretic bands (MW range 46,000-60,000), and a shift of the carbon-monoxide-reduced cytochrome P-450 spectral peak from 452 nm to 450 nm. These results suggest that alterations in cytochrome P-450 species related to benzo[a]pyrene metabolism might explain the modulation of this activity by nutritional effects.

Animals↗

PubMedDate not supplied

[Interaction of HIV-1 reverse transcriptase with new minor groove ligands and their conjugates with oligonucleotides].

The influence of new non-natural regular minor groove binders (MGB), containing 2-4 imidazole, pyrrole or thiazole residues, and their conjugates with oligonucleotides, on the polymerization reaction catalyzed by HIV-1 reverse transcriptase was analyzed. Various model template-primer complexes: poly(A)-oligo(U), poly(A)-oligo(dT), poly(dA)-oligo(U), poly(dA)-oligo(dT) and activated DNA were used. The concentration of oligopeptides, giving 50% inhibition (I50) of the RT-dependent polymerization reaction, was shown to depend strongly on the structure of template-primer complexes, number and type of the heterocycle rings in the MGBs analyzed. The range of I50 for the most of the compounds studied is 7.7 x 10(-3)-1.0 x 10(-5) M. The affinity of MGB is minimal for poly(A)-oligo(U). However, some of imidazole and pyrrole-containing MGBs demonstrated unusually high affinity (I50 = 3 x 10(-9)-4 x 10(-8) M) to the above template-primer in complex with RT. The affinity of conjugates of thiazolecarboxamides with oligonucleotides complementary or partially complementary to the template, is 1-4 orders higher compared to free thiazolecarboxamides. The possible reasons of the dependence of I50 values upon the structure of the template-primer complexes, the structure of MGB, and their conjugates with oligonucleotides are discussed.

HIV Reverse Transcriptase↗

PubMedDate not supplied

[Inhibition of the polymerization reaction, catalyzed by human immunodeficiency virus reverse transcriptase using model substrates by derivatives of oligo-1,3-thiazolecarboxamides].

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Animals↗

PubMedDate not supplied

[Interaction of human immunodeficiency virus reverse transcriptase with oligonucleotide derivatives containing polycyclic aromatic groups at the 5'-terminus].

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DNA Primers↗