Compounds containing free amino, hydroxyl or carbonyl groups can be activated by reaction with polyphosphate ester. tf the compoundc; contain a second functional group, polyconden-sations are possible; e.g. amino acids + polypeptides, carbohydrates + polysaccharides,
nucleotides + polynucleotides. In the presence of polyadenylic acid, polymerization of uridylic acid is speeded up tenfold. This mutual efect of complementary nucleotide strands constitutes the experimental basis for a hypothesis concerning the terrestrial origin of systems capable of self reproduction.
Durch Umsetzung rnit Polyphosphorsaureester lassen sich Verbindungen mit freier Amino-, Hydroxyl-oder Carbonylgruppe aktivieren. Enthalten die Verbindungen eine zweite funktionelle Gruppe, so werden Polykondensationen moglich: Aminosauren-* Polypeptide, Zucker -* Polysaccharide, Nucleotide --+ Polynucleotide. Polyadenylsaure beschleunigt die Polykondensation von Uridylsaure auf das mehr als 10-fache. Diese gegenseitige Beeinflussung komplernentarer Nucleotidstrange bildet die experimentelle Grundlage fur eine Theorie uber die Entstehung selbstvermehrungsfahiger Systeme im Lauf der Erdgeschichte.
The isolation and characterization of a specific chlorogenic acid esterase is described. The enzyme activity is measured by determination of the hydrolysis product caffeic acid. The enzyme had been concentrated by means of ultrafiltration and column-chromatography. The pH- and temperature optimum were 6.5 and 45 °C respectively. Divalent cations were not required for the enzyme activity. As other esterases, this enzyme is inhibited by di-isopropyl-phosphorofluoridate. The Km-value is 0.70 mᴍ chlorogenic acid, the molecular weight 240000. The described enzyme is specific for chlorogenic acid.
On the other hand a typical unspecific esterase like the pig liver esterases does not split chlorogenic acid.
The isoelectric focusing reveals several isoenzymes of chlorogenase within a pI-range of 4.0-4.5.
A method for the potentiometric titration of secondary phosphate groups in nucleic acids is described. Ribonucleic acids of yeast and of microsomes contain 5—6% secondary phosphate groups which cannot be removed by dialysis. The potentiometric method was applied to study several enzymatic hydrolyses and the non-enzymatic hydrolysis between pH 2.4 —1.8. The rate of hydrolysis for the purines and for the phosphate groups is approximately proportional to the H®-concentration. The constants of hydrolysis for ribonucleic acid and for deoxyribonucleic acid were determined. In DNA the depurinisation is 650 times faster than in RNA.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.