Normal stratum corneum and psoriatic scales were homogenized and a differential centrifugation was performed. The DNase activity of the individual fractions was investigated by micro-dis-electrophoresis. At pH 5 only in the 600xg pellet and 105.000xg supernatant of normal keratin DNase activity could be observed. However, all psoriatic fractions showed distinct enzyme activities. At pH 7.4 little psoriatic DNase activity could only be demonstrated in the 105.000xg supernatant. Except from the 15.000xg pellet all fractions of normal stratum corneum displayed marked activities. In addition the 105.000xg supernatant showed two different DNase bands.
DNA-binding proteins (DBP) of normal human dermis, epidermis, horny layer and psoriatic scales represent a tissue-specific group of mostly nuclear nonhistone proteins. To analyse their function, the different DBP fractions were examined concerning the presence of DNase, DNA-polymerase and RNA-polymerase activities. DBP of normal epidermis and horny layer contain four different DNases. One DNase of both DBP fractions is active only at pH 5.0. Three DNases of epidermal DBP are active at a pH-range from 5.0--8.5, while the corresponding DNases of horny layer-DBP are most active at pH 7.4. Probably these DNases have changed their pH-optimum during keratinisation. DBP of psoriatic scales include no activity of these three DNases and the pH 5.0-DNases seem to have reduced DNA-affinity. Human dermis DBP contain quite another set of four DNases which hardly can be correlated to the DNases of epidermal DBP. DNA-polymerase activities are present in each fraction and derive from different DNA-polymerases. Two DNA-polymerases with pI-values of 4.5 and 9.3 may correspond to beta- and alpha-DNA-polymerase of eukaryotes, respectively. Further activity of proteins which are focussed at pH 6.5--7.2 and 8.2 could be detected. The proteins represent either tissue-specific DNA-polymerases or further thymidine monophosphate incorporating enzymes. Contrary, RNA-polymerase activity could not be enriched from correlating extracts by DNA-cellulose chromatography.
Human skin epithelial-like cells (NCTC strain 2544) were grown in NCTC 135 medium. Neuraminidase and hyaluronidase were added to the growth medium. Cells were incubated 96 h at 36 degrees C. Growth rate and viscosity of cell suspensions were measured after forming single cells mechanically (mopping). With addition of neuraminidase and hyaluronidase, respectively, the growth rate remains unchanged. With neuraminidase a distinct raise in viscosity was achieved, whereas with hyaluronidase only a small effect was seen. The characteristic structure viscosity is maintained in all forms of the viscosity curves at different shear-rates.
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