Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Here, we report the biochemical characterization of mono(ADP-ribosyl)ated poly(ADP-ribose) polymerase (PARP) (EC 2.4.2. 30). PARP was effectively mono(ADP-ribosyl)ated both in solution and via an activity gel assay following SDS-PAGE with 20 microM or lower concentrations of [32P]-3'-dNAD+ as the ADP-ribosylation substrate. We observed the exclusive formation of [32P]-3'-dAMP and no polymeric ADP-ribose molecules following chemical release of enzyme-bound ADP-ribose units and high-resolution polyacrylamide gel electrophoresis. The reaction in solution (i) was time-dependent, (ii) was activated by nicked dsDNA, and (iii) increased with the square of the enzyme concentration. Stoichiometric analysis of the reaction indicated that up to four amino acid residues per mole of enzyme were covalently modified with single units of 3'-dADP-ribose. Peptide mapping of mono(3'-dADP-ribosyl)ated-PARP following limited proteolysis with either papain or alpha-chymotrypsin indicated that the amino acid acceptor sites for chain initiation with 3'-dNAD+ as a substrate are localized within an internal 22 kDa automodification domain. Neither the amino-terminal DNA-binding domain nor the carboxy-terminal catalytic fragment became ADP-ribosylated with [32P]-3'-dNAD+ as a substrate. Finally, the apparent rate constant of mono(ADP-ribosyl)ation in solution indicates that the initiation reaction catalyzed by PARP proceeds 232-fold more slowly than ADP-ribose polymerization.
 ...
PMID:Biochemical characterization of mono(ADP-ribosyl)ated poly(ADP-ribose) polymerase. 1019 6

The family of the poly(adenosine diphosphate-ribose) polymerase (PARP) proteins is directly involved in genomic stability, DNA repair, and apoptosis by DNA damage. In this study, we evaluated the role of PARP-1 in melanoma and its prognostic importance. We studied by immunohistochemistry and Western blot analysis PARP-1 expression in a selected series of 80 primary melanoma of the head and neck region. The results were correlated with tumor thickness and patient's outcome. A follow-up of at least 3 years was available. Fifteen cases of benign melanocytic nevi were used as controls. Normal melanocytes showed only scattered, focal nuclear positivity and were considered as negative for PARP-1 expression by immunohistochemistry (score, 0). Thirty cases of melanoma (37.5%) showed nuclear expression of PARP-1 in both radial and vertical growth phases. Western blot analysis showed the presence of a high signal for full-length PARP-1 only in the cases with high immunohistochemical (nuclear) expression of protein (score, ++/+++) in both radial and vertical growth phase. A significant correlation was present between PARP-1 expression in vertical growth phase and the thickness of tumor lesion (P = .014); all but one tumor measuring less than 0.75 mm showed no or low PARP-1 expression. No correlation was found between PARP-1 expression in radial growth phase and tumor thickness (P = .38, data not shown). These data suggest that PARP-1 overexpression is a potential novel molecular marker of aggressive cutaneous malignant melanoma and a direct correlation between PARP-1-mediated inhibition of the apoptosis and biologic behavior of cutaneous malignant melanoma.
 ...
PMID:Poly(adenosine diphosphate-ribose) polymerase 1 expression in malignant melanomas from photoexposed areas of the head and neck region. 1608 40