The deoxyribonuclease (DNase) activity of the dipteran (Chironomus thummi) salivary gland, measured both enzymatically and immunochemically, increases about 7-fold with the onset of metamorphosis. The increase in DNase activity occurs at a time when the activities of other enzymes and the total protein content are decreasing. The increased DNase activity is followed by glandular destruction. It...

The sequence selectivity of DNase 1 cleavage has been investigated by site-directed mutagenesis of a chemically synthesised gene. Two key DNA binding residues have been conservatively altered (Y76F and R41K) or have had their side-chains truncated (Y76A and R41A) and the effect on the cleavage of tyr T promoter DNA has been noted. It would appear from these studies that DNase 1 is not sensitive...

It has been recently recognized that lectins exhibit other activities besides hemagglutination. Previously we have found that purified lectin from Chelidonium majus showed DNase activity (Fik, Goździcka-Józefiak & Kedzia, 1995, Herba Polon. 41, 84-95). Comparison of lectin and DNase from the sap from leaves and roots of Chelidonium majus proved that both these compounds are composed of 24 kDa m...

Expression of the proto-oncogene c-myc is tightly regulated in vivo. Transcription of c-myc is assumed to be controlled by a number of positive and negative cis-acting control elements located upstream or within exon 1 and intron 1. However, these regulatory elements are not sufficient for c-myc expression after stable transfection or in transgenic mice. Transcription of c-myc in vivo thus requ...

In our work the antitumor and antimetastatic activities of RNase A and DNase I were studied using two murine models of pulmonary (Lewis lung carcinoma) and liver (hepatoma A-1) metastases. We found that intramuscular administration of RNase A at the dose range of 0.1-50 µ g/kg retarded the primary tumor growth by 20-40%, and this effect disappeared with the increase in RNase A dose over 0.5 mg/...

DNA ligase and DNase levels were measured in cell-free extracts from untreated mouse erythroleukemia (MEL) cells and from cells treated with dimethyl sulfoxide (Me2SO) to induce erythroid differentiation. The DNase activity present in the extracts was sensitive to inhibition by G-actin and was, therefore, presumed to be DNase I. When the MEL cells were induced to differentiate by culturing in t...

DNase A is a non-specific endonuclease of Fibrobacter succinogenes. The enzyme was purified to homogeneity and its properties studied both in vitro and in vivo. Magnesium but not calcium was essential for nucleolytic activity. Manganese ions substituted for magnesium but were less stimulatory. DNase A activity was markedly inhibited by either NaCl or KCl at concentrations greater than 75 mM. Th...

A mix of biocompatible macromolecules (poly(vinyl alcohol) (PVA) and poly(vinyl pyrrolidone) (PVP)) has been shown previously to enhance the physical stability of non-aqueous pharmaceutical suspensions. The aim of this work was to assess the feasibility of employing such a combination to facilitate the formulation of deoxyribonuclease I (DNase I) in a metered dose inhaler (MDI) using hydrofluor...