Muñoz Delgado, Encarnación

Person:
Muñoz Delgado, Encarnación

Name

Muñoz Delgado, Encarnación

publication.page.department

Universidad de Murcia. Departamento de Bioquímica y Biología MolecularA

Full item page

Search Results

Now showing 1 - 8 of 8

Open Access
Human butyrylcholinesterase components differ in aryl acylamidase activity
(De Gruyter Brill, 2008-03-27) Montenegro Arce, María Fernanda; Moral Naranjo, María T.; Páez de la Cadena, María; Campoy Menéndez, Francisco Javier; Muñoz Delgado, Encarnación; Vidal, Cecilio J.; Bioquímica y Biología Molecular A
Apart from its esterase activity, butyrylcholinesterase (BuChE) displays aryl acylamidase (AAA) activity able to hydrolyze o-nitroacetanilide (ONA) and its trifluoro-derivative (F-ONA). We report here that, despite amidase and esterase sites residing in the same protein, in human samples depleted of acetylcholinesterase the ratio of amidase to esterase activity varied depending on the source of BuChE. The much faster degradation of ONA and F-ONA by BuChE monomers (G1) of colon and kidney than by the tetramers (G4) suggests aggregation-driven differences in the AAA site between single and polymerized subunits. The similar ratio of F-ONAto butyrylthiocholine hydrolysis by serum G1 and G4 forms support structural differences in the amidase site according to the source of BuChE. The changing ratios of amidase to esterase activities in the human sources probably arise from post-translational modifications in BuChE subunits, the specific proportion of monomers and oligomers and the variable capacity of the tetramers for degrading ONA and F-ONA. The elevated amidase activity of BuChE monomers and the scant activity of the tetramers justify the occurrence of single BuChE subunits in cells as a means to sustain the AAA activity of BuChE which otherwise could be lost by tetramerization.
Metadata only
Solubilización y propiedades de la acetilcolinesterasa del sistema sarcotubular de músculo blanco de conejo
(Universidad de Murcia, 1985) Muñoz Delgado, Encarnación; Lozano Teruel, José Antonio; Vidal Moreno, Ceclio Jesús; Facultad de Ciencias Químicas y Matemáticas
Open Access
Acetyl-and butyrylcholinesterase activities decrease in human colon adenocarcinoma
(Springer, 2006-02) Montenegro Arce, María Fernanda; Ruiz Espejo, Francisco; Campoy Menéndez, Francisco Javier; Muñoz Delgado, Encarnación; Páez de la Cadena, María; Cabezas Herrera, Juan; Vidal, Cecilio J.; Bioquímica y Biología Molecular A
Apart from the hydrolysis of acetylcholine (ACh), acetyl- (AChE) and butyrylcholinesterase (BChE), through noncatalytic mechanisms, intervene in hematopoiesis, morphogenesis, and neurogenesis (Layer and Willbold, 1995; Soreq and Seidman, 2001). Cholinesterase (ChE) molecules occur as globular (G1, G2, and G4) and asymmetric (A4, A8, and A12) forms (Legay, 2000; Massoulié, 2002). The G species might display amphiphilic (GA) or hydrophilic (GH) properties (Perrier et al., 2002). The involvement of ChEs in tumorigenesis is supported by the measurement of ChE activity in tumors (García-Ayllón et al., 2001; Ruiz-Espejo et al., 2003), the amplification of ChE genes in leukemias and ovarian tumors, and the relationship between the expression of AChE and the aggressiveness of astrocytomas(Perry et al., 2002). This research was undertaken to determine whether ChE activity is altered in gut carcinomas.
Restricted
Muscular dystrophy by merosin deficiency decreases acetylcholinesterase activity in thymus of Lama2dy mice
(WILEY, 2005-08-31) Vidal Moreno, Cecilio Jesús; Nieto Cerón, Susana; Campoy Menéndez, Francisco Javier; Muñoz Delgado, Encarnación; Sánchez del Campo Ferrer, Luis; Bioquímica y Biología Molecular A
Half of congenital muscular dystrophy cases arise from laminin alpha 2 (merosin) deficiency, and merosin-deficient mice (Lama2dy) exhibit a dystrophic phenotype. The abnormal development of thymus in Lama2dy mice, the occurrence of acetylcholinesterase (AChE) in the gland and the impaired distribution of AChE molecules in skeletal muscle of the mouse mutant prompted us to compare the levels of AChE mRNAs and enzyme species in thymus of control and Lama2dy mice. AChE activity in normal thymus (mean +/- SD 1.42 +/- 0.28 mu mol acetylthiocholine/h/mg protein, U/mg) was decreased by similar to 50% in dystrophic thymus (0.77 +/- 0.23 U/mg) (p = 0.007), whereas butyrylcholinesterase activity was little affected. RT-PCR assays revealed variable levels of R, H and T AChE mRNAs in thymus, bone marrow and spinal cord. Control thymus contained amphiphilic AChE dimers (G(2)(A), 64%) and monomers (G(1)(A), 19%), as well as hydrophilic tetramers (G(4)(H), 9%) and monomers (G(1)(H), 8%). The dimers consisted of glycosylphosphatidylinositol-anchored H subunits. Western blot assays with anti-AChE antibodies suggested the occurrence of inactive AChE in mouse thymus. Despite the decrease in AChE activity in Lama2dy thymus, no differences between thymuses from control and dystrophic mice were observed in the distribution of AChE forms, phosphatidylinositol-specific phospholipase C sensitivity, binding to lectins and size of AChE subunits.
Open Access
The level of aryl acylamidase activity displayed by human butyrylcholinesterase depends on its molecular distribution.
(Elsevier, 2008-09-25) Montenegro Arce, María Fernanda; Moral Naranjo, M. T.; Páez de la Cadena, M.; Muñoz Delgado, Encarnación; Vidal, C. J.; Campoy Menéndez, Francisco Javier; Bioquímica y Biología Molecular A
Butyrylcholinesterase (BuChE) and acetylcholinesterase (AChE) display both esterase and aryl acylamidase (AAA) activities. Their AAA activity can be measured using o-nitroacetanilide (ONA). In human samples depleted of acetylcholinesterase, we noticed that the ratio of amidase to esterase activities varied depending on the source, despite both activities being due to BuChE. Searching for an explanation, we compared the activities of BuChE molecular forms in samples of human colon, kidney and serum, and observed that BuChE monomers (G1) hydrolyzed o-nitroacetanilide much faster than tetramers (G4). This fact suggested that association might cause differences in the AAA site between single and polymerized subunits. This and other post-translational modifications in BuChE subunits probably determine their level of AAA activity. The higher amidase activity of monomers could justify the presence of single BuChE subunits in cells as a way to preserve the AAA activity of BuChE, which could be lost by oligomerization.
Open Access
Cholinesterases are down-expressed in human colorectal carcinoma
(Springer, 2006-08-11) Montenegro Arce, María Fernanda; Ruiz Espejo, Francisco; Campoy, F. J.; Muñoz Delgado, Encarnación; Páez de la Cadena, M.; Rodríguez-Berrocal, F. J.; Vidal, C. J.; Bioquímica y Biología Molecular A
The aberrations of cholinesterase (ChE) genes and the variation of ChE activity in cancerous tissues prompted us to investigate the expression of ChEs in colorectal carcinoma. The study of 55 paired specimens of healthy (HG) and cancerous gut (CG) showed that acetylcholinesterase (AChE) activity fell by 32% and butyrylcholinesterase (BuChE) activity by 58% in CG. Abundant AChE-H, fewer AChE-T, and even fewer AChE-R and BuChE mRNAs were observed in HG, and their content was greatly diminished in CG. The high level of the AChE-H mRNA explains the abundance of AChE-H subunits in HG, which as glycosylphosphatidylinositol (GPI)-anchored amphiphilic AChE dimers (GA2 ) and monomers (GA1) account for 69% of AChE activity. The identification of AChE-T and BuChE mRNAs justifies the occurrence in gut of A12, GH4 and PRiMA-containing GA4 AChE forms, besides GH4 , GA4 and GH1 BuChE. The down-regulation of ChEs might contribute to gut carcinogenesis by increasing acetylcholine availability and overstimulating muscarinic receptors.
Open Access
The expression of cholinesterases in human renal tumours varies according to their histological types
(Elsevier, 2008-09-25) Montenegro Arce, María Fernanda; Muñoz Delgado, Encarnación; Morote García, Julio César; Campoy Menéndez, Francisco Javier; Cabezas Herrera, Juan; Kovacs, Gyula; Vidal, Cecilio J.; Bioquímica y Biología Molecular A
The change in the expression of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activities in neoplastic colon and lung prompted us to study the possible effect of cancer on the expression of cholinesterases (ChEs) in kidney. Samples of papillary renal cell carcinoma (pRCC), conventional RCC (cRCC), chromophobe RCC (chRCC) and renal oncocytoma (RON), beside adjacent non-cancerous tissues, were analyzed. In pRCC both AChE and BuChE activitieswere statistically increased; in cRCC and chRCC onlyAChE activity increased and in RON neither AChE nor BuChE activities were affected. Abundant amphiphilic AChE dimers (G2A) and fewer monomers (G1A) were identified in healthy kidney as well as in all tumour classes. Incubation with PIPLC revealed glycosylphosphatidylinositol in AChE forms. BuChE is distributed between principal G4H, fewer G1H, and much fewer G4A and G1A species. RT-PCR showed similar amounts of AChE-H, AChE-T and BuChE mRNAs in healthy kidney. Their levels increased in pRCC but not in the other tumour types. The data support the idea that, as in lung tumours, in renal carcinomas expression of ChE mRNAs, biosynthesis of molecular components and level of enzyme activity change according to the specific kind of cell from which tumours arise.
Open Access
Targeting of acetylcholinesterase to lipid rafts of muscle
(Elsevier, 2008-09-25) Moral Naranjo, M. T.; Montenegro Arce, María Fernanda; Muñoz Delgado, Encarnación; Campoy, M. J.; Vidal, C. J.; Bioquímica y Biología Molecular A
Despite the great progress made in setting the basis for the molecular diversity of acetylcholinesterase (AChE), an explanation for the existence oftwo types of amphiphilic subunits, with and without glicosylphosphatidylinositol (GPI) (Types I and II), has not been provided yet. In searching whether, as for the deficiency of dystrophin, that of merosin (laminin- 2 chain) alters the number of caveolae in muscle, a high increase in caveolin-3 (Cav3) was observed in the Triton X-100-resistant membranes (TRM) isolated from muscle of merosin-deficient dystrophic mice (Lama2dy). The rise in Cav3 was accompanied by that of non-caveolar lipid rafts, as showed by the greater ecto-5 -nucleotidase (eNT) activity, a marker of non-caveolar rafts, in TRM of dystrophic muscle. The observation of AChE activity in TRM, the increased levels of rafts and raft-bound AChE activity in merosin-deficient muscle and the presence of phospholipase C-sensitive AChE dimers in TRM supported targeting of glypiated AChE to rafts. This issue and the involvement of TRM in conveying nicotinic receptors to the neuromuscular junction and particular muscarinic receptors to cardiac sarcolemma strongly support a role for lipid rafts in targeting ACh receptors and glypiated AChE. Their nearby location in the surface membrane may provide cells with a fine tuning for regulating cholinergic responses.