Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.23.17 (PCE)
 1,301 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Studies have shown that inflammatory (cholesterol esterase, CE) and salivary (pseudo-cholinesterase, PCE) enzymes can cause the breakdown of bisphenol-A diglycidyl dimethacrylate (bisGMA) and triethylene glycol dimethacrylate (TEGDMA) components from composite resins. Based on the above consideration, it was desired to show how CE- and PCE-catalyzed hydrolysis of resin components was dependent on the enzymes' concentration and to determine their distinct specificities (if any) towards resin components. Photopolymerized model composite resin samples (60% weight fraction silanated barium glass filler) based on bisGMA and TEGDMA monomers (55/45 weight ratio of the matrix, respectively) were incubated with PBS and either 0.01, 0.05, 0.1 or 1 unit/ml of CE or PCE for 16 days (pH 7.0, 37 degrees C). Incubation solutions were analyzed by high-performance liquid chromatography (HPLC), UV spectroscopy and mass spectrometry. The composite samples were characterized by scanning electron microscopy (SEM). Degradation rates of bisGMA and TEGDMA monomers were assessed. The results showed that CE had a greater specificity towards cleaving bisGMA while PCE showed a greater specificity towards TEGDMA. A strong enzyme concentration dependence was observed which suggests that the level of degradation products generated for a material will depend on the esterase make-up of an individual's saliva in combination with the specific formulation of monomer components used.
 ...
PMID:Biodegradation of a dental composite by esterases: dependence on enzyme concentration and specificity. 1453 61

Esterase activities similar to those of cholesterol and pseudocholine esterases (CE and PCE, respectively) have been detected within whole human saliva. Since commercial CE has been shown to possess distinct activity relative to PCE for select components in dental composites, it is hypothesized that esterases isolated from human saliva will also show selectivity towards specific monomer elements within the composites. The objective of this work was to carry out the isolation of these activities from whole human saliva and study their individual effects on resin monomers such as Bis-phenyl glycidyl dimethacrylate (aromatic structure) and triethylene glycol dimethacrylate (hydrophilic structure), and on cured composites containing the latter monomers. Human saliva samples were processed, fractionated on a gel filtration column and assayed for CE and PCE-like activity. Selected fractions were incubated at 37 degrees C with the above monomers and select commercial composites. Degradation was monitored using high-performance liquid chromatography. The fraction with the highest cholesterol esterase-like character preferentially degraded the aromatic monomer and significantly degraded more of the composite's material relative to a fraction containing low amounts of the cholesterol esterase activity but elevated pseudocholine esterase-like activity. Hence, it was concluded that select salivary esterases had preferences for distinct composite resin components.
 ...
PMID:Identifying enzyme activities within human saliva which are relevant to dental resin composite biodegradation. 1568 49