Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.22.1 (DNase II)
 429 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chromatin from trout testis at an early stage of development was digested with DNase II (deoxyribonucleate 3'-oligonucleotidohydrolase; EC 3.1.4.6), and the solubilized products were fractionated into Mg2+-soluble and -insoluble components. An examination of the histones from these fractions by one- and two-dimensional polyacrylamide gels showed that the highly acetylated species of histone H4 (di-, tri-, and tetra-acetylated) were associated mainly with the Mg2+-soluble material. Digestion of this chromatin fraction with pancreatic ribonuclease converted more than half of it to an insoluble state, and the acetylated H4 remained associated with the precipitated fraction. No changes in the other histones were noted, but two other basic proteins were also found to be associated with the Mg2+-soluble fraction. Since this fraction is enriched in transcribing gene sequences, it is concluded that the histone H4 of active genes is present in a highly acetylated state.
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PMID:Acetylated histone H4 is preferentially associated with template-active chromatin. 27 72

Transition of bovine ribonuclease A from its monomeric to a dimeric form changes the pattern of enzymic activity response to ionic strength [Sorrentino, S., Carsana, A., Furia, A., Doskocil, J., and Libonati, M. (1980) Biochim. Biophys. Acta. 609, 40-52]. To see whether this phenomenon could be common to other enzyme-substrate systems, the action of various dimeric and monomeric enzymes (ox pancreas deoxyribonuclease, hog spleen acid deoxyribonuclease, bovine seminal ribonuclease, egg-white lysozyme, and papain) on polyelectrolytic substrates has been studied under different conditions of ionic strength. Dimerization of ox pancreas deoxyribonuclease, lysozyme and papain was obtained by cross-linkage with dimethyl suberimidate. The main results of the investigation, similar to those obtained with ribonuclease A, are the following. 1. Enzyme monomers and dimers show markedly different patterns of activity response to ionic strength at given pH values: the reactions catalyzed by monomeric enzymes are highly modulated by salt, whereas those catalyzed by dimeric enzymes are not. In particular, at the reaction optimum the monomeric form of an enzyme is significantly more active than the dimeric one. 2. The optimum of the reaction catalyzed by a dimeric enzyme is shifted to higher ionic strengths in comparison with that of the reaction catalyzed by a monomeric enzyme. A model is proposed that could explain these results on the basis of the influence of ionic strength on the intramolecular dynamics of the enzyme molecule and its non-specific interactions with polyelectrolytic substrates.
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PMID:Dimerization of deoxyribonuclease I, lysozyme and papain. Effects of ionic strength on enzymic activity. 628 87