Alterations of prolyl endopeptidase activity in the plasma of children with autistic spectrum disorders

BACKGROUND: Prolyl Endopeptidase (PEP, EC 3.4.21.26), a cytosolic endopeptidase, hydrolyses peptide bonds on the carboxyl side of proline residue in proteins with a relatively small molecular weight. It has been shown that altered PEP activity is associated with various psychological diseases such as schizophrenia, mania and depression. Autistic Spectrum Disorders (ASD) are neuropsychiatric and behavioural syndromes affecting social behaviours and communication development. They are classified as developmental disorders. The aim of this study was to examine the hypothesis that PEP activity is also associated with ASDs. METHODS: Fluorometric assay was used to measure PEP activity in EDTA plasma in children with ASD (n = 18) aged 4–12 years (mean ± SD: 7.9 ± 2.5). These results were then compared to PEP activity in a control group of non-ASD children (n = 15) aged 2–10 years (mean ± SD: 6.4 ± 2.2). RESULTS: An alteration in PEP activity was found in the children with ASD compared to the control group. There was much greater variation of PEP activity in the group of ASD children when compared to the controls (SD= 39.9 and SD 9.6, respectively). This variation was significant (p < 0.0005), although the mean level of PEP activity in the group of ASD children was slightly higher than in the control group (124.4 and 134.1, respectively). CONCLUSION: Our preliminary finding suggests a role for PEP enzyme in the pathophysiology of autism but further research should be conducted to establish its role in the aetiology of psychiatric and neurological disorders, including autism and related spectrum disorders

Chymase-Dependent Generation of Angiotensin II from Angiotensin-(1-12) in Human Atrial Tissue

Since angiotensin-(1-12) [Ang-(1-12)] is a non-renin dependent alternate precursor for the generation of cardiac Ang peptides in rat tissue, we investigated the metabolism of Ang-(1-12) by plasma membranes (PM) isolated from human atrial appendage tissue from nine patients undergoing cardiac surgery for primary control of atrial fibrillation (MAZE surgical procedure). PM was incubated with highly purified 125I-Ang-(1-12) at 37°C for 1 h with or without renin-angiotensin system (RAS) inhibitors [lisinopril for angiotensin converting enzyme (ACE), SCH39370 for neprilysin (NEP), MLN-4760 for ACE2 and chymostatin for chymase; 50 µM each]. 125I-Ang peptide fractions were identified by HPLC coupled to an inline γ-detector. In the absence of all RAS inhibitor, 125I-Ang-(1-12) was converted into Ang I (2±2%), Ang II (69±21%), Ang-(1-7) (5±2%), and Ang-(1-4) (2±1%). In the absence of all RAS inhibitor, only 22±10% of 125I-Ang-(1-12) was unmetabolized, whereas, in the presence of the all RAS inhibitors, 98±7% of 125I-Ang-(1-12) remained intact. The relative contribution of selective inhibition of ACE and chymase enzyme showed that 125I-Ang-(1-12) was primarily converted into Ang II (65±18%) by chymase while its hydrolysis into Ang II by ACE was significantly lower or undetectable. The activity of individual enzyme was calculated based on the amount of Ang II formation. These results showed very high chymase-mediated Ang II formation (28±3.1 fmol×min−1×mg−1, n = 9) from 125I-Ang-(1-12) and very low or undetectable Ang II formation by ACE (1.1±0.2 fmol×min−1×mg−1). Paralleling these findings, these tissues showed significant content of chymase protein that by immunocytochemistry were primarily localized in atrial cardiac myocytes. In conclusion, we demonstrate for the first time in human cardiac tissue a dominant role of cardiac chymase in the formation of Ang II from Ang-(1-12)

Diseño del edificio para laboratorio y oficinas en la autoridad para el manejo sustentable de la cuenca y el Lago de Amatitlán (AMSA) y mapeo de uso de suelos por el método Corine Land Cover y Sistema de Información Geográfica (ARCGIS) para Mixco, Guatemala

Cumplir los parámetros establecidos en el AGIES para el diseño del edificio de dos niveles con mampostería reforzada, así colaborar con el desarrollo del laboratorio para la reducción de contaminación

Active Center Studies on Bacterial Luciferase: Modification of the Enzyme With 2,4-Dinitrofluorobenzene

89 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1980.Bacterial luciferase catalyzes the mixed-function oxidation of a long-chain saturated aldehyde and FMNH(,2) to yield the carboxylic acid, FMN and blue-green light. The enzyme is inactivated by 2,4-dinitrofluorobenzene (FDNB) with an observed second-order rate constant (k(,2(obs))) of 157 M('-1) min('-1) at pH 7.0, 25(DEGREES); activity is not recovered upon treatment with 2-mercaptoethanol (thiolysis), demonstrating that the inactivation is the result of reaction with one or more amino groups. The dinitrophenyl moiety is incorporated into the (alpha) subunit approximately twice as fast as it is incorporated into the (beta) subunit; the rate of inactivation is nearly identical to the rate of incorporation into the (alpha)(beta) dimer. The incorporation of 1 mole DNP/(alpha)(beta) results in complete inactivation. Modification of either (alpha) or (beta) is sufficient to cause inactivation. Analysis of acid hydrolysates of modified enzyme showed that the most likely sites of modification are the NH(,2)-terminal methionyl residues of the two subunits to form the acid-labile DNP-methionine rather than the acid-stable (epsilon)-DNP-lysine.The luciferase is protected from inactivation by binding of long-chain aldehydes or FMN. Following modification by FDNB, the enzyme has lost measurable FMNH(,2) binding.The apparent pK(,a) of the amino groups, determined by analysis of the pH dependence of the inactivation reaction, was 9.4. This value is too high to allow correlation with the pH-activity profile of the enzyme (Nicoli, M. Z., Meighen, E.A., and Hastings, J. W. (1974) J. Biol. Chem. 249, 2385-2392). The catalytic function (if any) for the reactive amino groups remains unknown.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD