Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.27 (thermolysin)
 1,894 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The dialdehyde produced by the periodate cleavage of the ribose moiety of uridine 5'-diphosphate (UDP) has been used as an affinity label for the UDP-galactose/UDP binding site of galactosyltransferase from bovine colostrum. This derivative causes progressive inactivation of galactosyltransferase at a rate dependent on its concentration, and under certain conditions is a competitive inhibitor with respect to UDP-galactose. The substrate UDP-galactose protects the enzyme from inactivation. The inactivation is also dependent on Mn2+ concentration in a range that implies that the binding of Mn2+ at site I is a prerequisite for the binding of the UDP derivative. The inactivation can be progressively reversed by nitrogenous bases, or stabilized by KBH4 reduction, which is consistent with the hypothesis that a Schiff base has formed with a lysine residue. Galactosyltransferase was inactivated with a [3H]UDP derivative and the predominant labeled peptide, from thermolysin digestion, isolated and characterized as: Ser-Gly-Lys-UDP.
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PMID:Affinity labeling of bovine colostrum galactosyltransferase with a uridine 5'-diphosphate derivative. 95 73

For facilitating photochemical and toxicological studies an ex vivo skin model was developed in our laboratory using skin from domestic pigs. The model comprised the use of a complete skin piece, including the dermis and stratum corneum, of bigger areas to make future topical applications easier. Fully differentiated skin explants (5 x 50 mm, thickness 5 mm) were irradiated with ultraviolet B (UVB; 1-10 kJ/m2; 6 W/m2). Directly thereafter they were brought in culture (Dulbeccos modified Eagles medium containing hydrocortisone; air/liquid interface) for a maximum of 144 h. In nonirradiated skin explants, signs of tissue degeneration were observed after 48 h in culture (hematoxylin and eosin, light microscope). However, keratinocytes, isolated enzymatically (thermolysin and trypsin) at different time intervals in culture from nonirradiated skin explants showed negligible loss in viability (trypan blue exclusion) and increased apoptosis (terminal deoxynucleotidyl transferase-mediated deoxy uridine triphosphatase nick end labeling assay) for up to 72 h. Explants irradiated with a single dose of UVB showed a clear and reproducible dose- and time-dependent tissue degeneration, loss in keratinocyte viability and increase in apoptosis compared with nonirradiated explants at the same time interval. In conclusion, the presently designed ex vivo pig skin model can be a useful and cheap tool for future investigations of short-term UV-induced effects in combination with phototoxic and photoprotective compounds.
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PMID:Time and dose-related ultraviolet B damage in viable pig skin explants held in a newly developed organ culture system. 1136 71