RESUMO
A peptide fraction from the mitochondrial DNA of calf's liver was isolated using Drouin's method (1). This peptide fraction, which was extracted at pH 9.5 from an extensively purified mitochondrial DNA (2), has been shown to exert an in vitro regulatory role on the transcription and duplication activity of DNA (3). The same fraction also binds with mitochondrial DNA with a high affinity constant and stabilizes DNA from calf's thymus against thermal denaturation. The peptides from mitochondrial DNA have been subfractionated by fingerprinting-like techniques and one of them has been sequenced.
Assuntos
Replicação do DNA/efeitos dos fármacos , DNA Mitocondrial/metabolismo , Mitocôndrias Hepáticas/metabolismo , Peptídeos/química , Peptídeos/farmacologia , Moldes Genéticos , Transcrição Gênica/efeitos dos fármacos , Sequência de Aminoácidos , Animais , Bovinos , DNA Mitocondrial/efeitos dos fármacos , DNA Polimerase Dirigida por DNA/metabolismo , RNA Polimerases Dirigidas por DNA/metabolismo , Eletroforese em Gel de Poliacrilamida , Espectroscopia de Ressonância Magnética , Dados de Sequência Molecular , Peso Molecular , Peptídeos/isolamento & purificação , Espectrofotometria Infravermelho , Espectrofotometria UltravioletaRESUMO
Authors tested "in vitro" action of a low molecular weight peptide fraction extracted by mitochondrial DNA from calf liver. The fraction acts upon duplication performed by E. Coli DNA polymerase I on poli dAT dAT template inhibiting chain elongation. The authors hypothesize that a similar role is exerted by this fraction "in vitro" on mitochondrial DNA template.
Assuntos
Replicação do DNA/efeitos dos fármacos , DNA Mitocondrial/análise , Mitocôndrias Hepáticas/química , Peptídeos/farmacologia , Animais , Bovinos , Peso MolecularRESUMO
Authors studied the effects of thyroid hormones and their diasteroisomers and 3,5-diiodothyronine (LT2) on the fluidity properties of inner mitochondrial membrane (IMM) by specifical fluorescent probe for the internal zone of biological membranes, the 1,6-diphenyl-1,3,5-hexatriene (DPH). The studied parameters are Arrhenius and Perrin plots. The DPH shows a decreased fluorescence quenching in the presence of both T3 and T4. The maximum effect is observed with 2 nM LT2. LT2 is more effective than LT3 in the central zone. The data confirm the selective action of LT3 and LT4 on IMM fluidity.