Degradation of peroral administered drugs by various enzymes in the gastrointestinal tract has proven to be troublesome for the absorption' and bioavailability of protein and peptide drugs. Mucoadhesive polymers such as poly(acrylates) have proven to inhibit protease enzymes responsible for initiating digestion of peptide drugs. Enzyme inhibitors have unique chemical properties enabling it to interact with enzymes to form complexes with such enzymes prohibiting it from functioning properly. Anionic carboxymethylated chitosan derivatives such as N,N-dicarboxymethyl chitosan and N, O-carboxymethyl chitosan display unique structural similarities to enzyme inhibitors being anionic polymers that may interact with bi-valent cations... / Thesis (M.Sc. (Pharm.))--North-West University, Potchefstroom Campus, 2004.

Degradation of peroral administered drugs by various enzymes in the gastrointestinal tract has proven to be troublesome for the absorption' and bioavailability of protein and peptide drugs. Mucoadhesive polymers such as poly(acrylates) have proven to inhibit protease enzymes responsible for initiating digestion of peptide drugs. Enzyme inhibitors have unique chemical properties enabling it to interact with enzymes to form complexes with such enzymes prohibiting it from functioning properly. Anionic carboxymethylated chitosan derivatives such as N,N-dicarboxymethyl chitosan and N, O-carboxymethyl chitosan display unique structural similarities to enzyme inhibitors being anionic polymers that may interact with bi-valent cations... / Thesis (M.Sc. (Pharm.))--North-West University, Potchefstroom Campus, 2004.

Proteins containing Kunitz domain are mostly inhibitors of serine proteases. Their general characteristic is the presence of three disulfide bonds and small sizes around 6-10 kDa, although sometimes they consist of several Kunitz domains or they are part of more complex proteins. Their function is usually related to the regulation of physiological and proteolytic processes, but also to an interaction with pathogens or other defense mechanisms, such as being part of the sea anemone mucus or the venom of snakes and other invertebrates. We focused on Kunitz proteins in Eudiplozoon nipponicum, a helminth of the class Monogenea parasiting on gills of common carp (Cyprinus carpio). In the transcriptome of this parasite, several sequences with Kunitz domain have been identified based on similarities with the one already described Kunitz protein, EnKT1, suggesting that this parasite, like other bloodfeeding parasites, uses a whole set of these serine protease inhibitors with other specific functions. Several sequences with the Kunitz domain found in the transcriptome were verified by PCR and optionally supplemented by RACE-PCR. One protein, called EnKC1, was subsequently produced by recombinant expression in E. coli cells of SHuffleTM and Rosetta Gami B strains. Recombinant protein with the Kunitz domain...

No / Buddlejol (1), a new sterol, has been isolated from the ethyl acetate soluble fraction of the antispasmodic plant Buddleja asiatica along with stigmasterol (2), lignoceric acid (3), taraxerol (4) and alpha-amyrin (5), respectively. The structure of Buddlejol (1) was established as (24S)-stigmast-5,22-diene-7 beta-ethoxy-3 beta-ol by spectral analysis and comparison with closely related structures. Buddlejol revealed to be a competitive inhibitor of chymotrypsin with the Ki value of 10.60 A mu M as indicated by Lineweaver-Burk and Dixon plots and their re-plots against its chymotrypsin inhibition assay, while the other compounds showed less inhibitory potential. The bioassay-guided isolation was stimulated by the preliminary cytotoxic screening of various fractions of B. asiatica.

The main purpose of the master thesis project is to investigate the influence of selected serine protease inhibitors (SPI) on the catalytic action of the serine proteases chymotrypsin and trypsin, in a conjugated and non-conjugated state. The inhibitors included for this study were extracted from Solanum tuberosum, i.e.common potato. The purification method included in this study consist of crude extraction by mixer, followed by a salt-out procedure with ammonium sulphate. Further purification steps were cation exchange chromatography and, finally, gel filtration to obtain SPI of high purity. The purified sample was then characterized by SDS-page and kinetic activity measurement of trypsin and chymotrypsin action on synthetic substrate derivate, N-Benzoyl-DL-arginine-4-nitroanilide hydrochloride (BAPA) and N-Succinyl-L-phenylalanine-p-nitroaniline (SFpNA) respectively. The characterization showed inhibitory inactivation of both pancreatic proteases. This would indicate successful extraction of SPI. To investigate inhibitory action in a conjugated state, either enzyme or inhibitor was immobilized onto aluminium oxide membranes. Then two different experimental setups were tested, called experiment 1 and 2. In experiment 1, the inhibitor was immobilized and the interaction was monitored from a retention shift of enzyme flow-through compared to a blank column, using detection at 280 nm of the enzyme. In experiment 2 the enzyme was instead immobilized and a mixture of inhibitor and substrate was circulated with monitoring of the catalytic activity. The main goal was thus to measure the effects on the kinetics in the conjugated state compared to enzyme and inhibitor in the free state. The result from both experiment 1 and 2 did not yield consistent and reliable result so the discussed method should be regarded as preliminary results. The study also includes investigation of inhibitor-enzyme interaction as revealed by molecular mass data to determine complex formation. This part was conducted with static light scattering analysis to determine the stoichiometry for the interaction between pancreas proteases and the inhibitor. Results from light scattering showed promising indication of many-to-one interaction between enzyme and inhibitor, which have been seen by previous studies. It should be considered a preliminary result as complex formation does not exclude aggregation of enzymes or inhibitor in the solution.

A pancreatite crônica é uma desordem complexa, na qual a interação entre fatores ambientais e genéticos resulta na enfermidade. O presente estudo incluiu 148 pacientes com diagnóstico de pancreatite crônica, 110 etilistas crônicos e 297 controles sadios com o objetivo de investigar a frequência de tabagismo e das mutações N34S e P55S do gene SPINK1 e R254W do gene CTRC nesta população. Foi aplicado questionário presencial e realizada reação de sequenciamento para a pesquisa das mutações genéticas, após assinatura do Termo de Consentimento Livre e Esclarecido. Os portadores de pancreatite crônica possuíam etiologia alcoólica em 74% das vezes e idiopática em 26%. A pancreatite alcoólica apresentou-se de maneira distinta da pancreatite crônica idiopática, sendo que o primeiro grupo é composto por maior prevalência do gênero masculino (88,18% versus 34,21%), por maior média de idade (55,64 anos versus 45,20 anos), menor frequência de caucasianos (63,89% versus 84,21%), menor escolaridade (23,30% concluíram ensino médio ou superior versus 57,89%) e maior frequência de repercussões da doença, como diarréia (54,21% versus 24,24%), emagrecimento (56,07% versus 24,24%), diabete melito (57,94% versus 36,36%) e ocorrência de pseudocistos pancreáticos (31,78% versus 12,12%), repercussões estas que não foram acompanhadas de maior frequência de alterações morfológicas, como calcificações pancreáticas ou dilatação do ducto pancreático principal. A frequência de tabagismo foi significativamente maior em pacientes com pancreatite crônica alcoólica do que em etilistas sem pancreatite crônica, podendo ser considerado cofator de risco para o desenvolvimento da pancreatite crônica entre alcoolistas (p = 0,002); a frequência da mutação N34S do gene SPINK1 em pacientes com pancreatite crônica foi de 3,38%, maior do que a frequência de 0,49% encontrada nos grupos controle (p = 0,016); a frequência de 2,03% da mutação P55S do gene SPINK1 e a frequência de 0,67% da mutação R254W do gene CTRC, encontradas nos pacientes com pancreatite crônica, não diferiram estatisticamente quando comparadas às frequências, de 0,49% de ambas mutações, encontradas nos grupos controle. (p = 0,120 e 0,751). Pela investigação da associação de tabagismo e da mutação N34S do gene SPINK1 com as características clínicas e morfológicas da pancreatite crônica, verificou-se que a mutação N34S não se associou a maior gravidade da apresentação clínica ou morfológica da pancreatite crônica; no entanto o tabagismo associou-se a maior frequência de diabete melito entre os portadores de pancreatite crônica. Concluiuse que o tabagismo e a mutação N34S do gene SPINK1 podem ser considerados cofatores de risco para o desenvolvimento da pancreatite crônica / Chronic pancreatitis is a complex disorder in which the interaction between environmental and genetic factors results in the disease. This study included 148 patients with chronic pancreatitis, 110 chronic alcoholics and 297 healthy controls in order to investigate the frequency of smoking and N34S and P55S mutation of SPINK1 gene and R254W of CTRC gene in this population. A questionnaire was applied and gene sequencing was done, after having the Informed Consent Statement. Those with chronic pancreatitis had alcoholic etiology in 74% of cases and idiopathic in 26%. Alcoholic pancreatitis presented in a distinct way of idiopathic chronic pancreatitis. The first group is composed of a higher prevalence of males (88.18% versus 34.21%), by higher mean age (55.64 years versus 45.20 years), lower frequency of Caucasians (63.89% versus 84.21%), lower education (23.30% completed secondary or higher education versus 57.89%) and worst impact from the disease such as diarrhea (54.21% versus 24.24%), weight loss (56.07% versus 24.24%), diabetes mellitus (57.94% versus 36.36%) and occurrence of pancreatic pseudocysts (31.78% versus 12 , 12%). These effects were not accompanied by increased frequency of morphological changes, such as pancreatic calcifications or dilation of the main pancreatic duct. The frequency of smoking was significantly higher in patients with alcoholic pancreatitis than in alcoholics without chronic pancreatitis, therefore tabagism may be considered as a cofactor for the development of chronic pancreatitis among alcoholics (p = 0.002); the frequency of N34S mutation of SPINK1 gene in patients with chronic pancreatitis was 3.38%, higher than the rate of 0.49% found in the control groups (p = 0.016); the frequency of 2.03% of the P55S mutation of SPINK1 gene and the frequency of 0.67% of the CTRC gene R254W mutation found in patients with chronic pancreatitis were not statistically different when compared to the frequencies of 0.49% of both mutations, found in the control groups. (p = 0.120 and 0.751) For the investigation of the association of smoking and N34S mutation of SPINK1 gene with the clinical and morphological features of chronic pancreatitis, it was noticed that the N34S mutation did not determine a greatest severity in the presentation of chronic pancreatitis, however smoking was associated with a higher frequency of diabetes mellitus in patients with chronic pancreatitis. It was concluded that smoking and the N34S mutation of SPINK1 gene are positively correlated with chronic pancreatitis

La digestion enzymatique des protéines est une méthode de base pour les études protéomiques ainsi que pour le séquençage en mode « bottom-up ». Les enzymes sont ajoutées soit en solution (phase homogène), soit directement sur le gel polyacrylamide selon la méthode déjà utilisée pour l’isolation de la protéine. Les enzymes protéolytiques immobilisées, c’est-à-dire insolubles, offrent plusieurs avantages tels que la réutilisation de l’enzyme, un rapport élevé d’enzyme-sur-substrat, et une intégration facile avec les systèmes fluidiques. Dans cette étude, la chymotrypsine (CT) a été immobilisée par réticulation avec le glutaraldehyde (GA), ce qui crée des particules insolubles. L’efficacité d’immobilisation, déterminée par spectrophotométrie d’absorbance, était de 96% de la masse totale de la CT ajouté. Plusieurs différentes conditions d’immobilisation (i.e., réticulation) tels que la composition/pH du tampon et la masse de CT durant la réticulation ainsi que les différentes conditions d’entreposage tels que la température, durée et humidité pour les particules GA-CT ont été évaluées par comparaison des cartes peptidiques en électrophorèse capillaire (CE) des protéines standards digérées par les particules. Les particules de GA-CT ont été utilisés pour digérer la BSA comme exemple d’une protéine repliée large qui requit une dénaturation préalable à la digestion, et pour digérer la caséine marquée avec de l’isothiocyanate de fluorescéine (FITC) comme exemple d’un substrat dérivé afin de vérifier l’activité enzymatique du GA-CT dans la présence des groupements fluorescents liés au substrat. La cartographie peptidique des digestions par les particules GA-CT a été réalisée par CE avec la détection par absorbance ultraviolet (UV) ou fluorescence induite par laser. La caséine-FITC a été, en effet, digérée par GA-CT au même degré que par la CT libre (i.e., soluble). Un microréacteur enzymatique (IMER) a été fabriqué par immobilisation de la CT dans un capillaire de silice fondu du diamètre interne de 250 µm prétraité avec du 3-aminopropyltriéthoxysilane afin de fonctionnaliser la paroi interne avec les groupements amines. Le GA a été réagit avec les groupements amine puis la CT a été immobilisée par réticulation avec le GA. Les IMERs à base de GA-CT étaient préparé à l’aide d’un système CE automatisé puis utilisé pour digérer la BSA, la myoglobine, un peptide ayant 9 résidus et un dipeptide comme exemples des substrats ayant taille large, moyenne et petite, respectivement. La comparaison des cartes peptidiques des digestats obtenues par CE-UV ou CE-spectrométrie de masse nous permettent d’étudier les conditions d’immobilisation en fonction de la composition et le pH du tampon et le temps de réaction de la réticulation. Une étude par microscopie de fluorescence, un outil utilisé pour examiner l’étendue et les endroits d’immobilisation GA-CT dans l’IMER, ont montré que l’immobilisation a eu lieu majoritairement sur la paroi et que la réticulation ne s’est étendue pas si loin au centre du capillaire qu’anticipée. / Digesting proteins using proteolytic enzymes is a standard method in proteomic studies and bottom-up protein sequencing. Enzymes can be added in solution or gel phase depending on how the protein has been isolated. Immobilized, i.e., insoluble, proteolytic enzymes offer several advantages such as reusability of enzyme, high enzyme-to-substrate ratio, and integration with fluidic systems. In this study, we prepared glutaraldehyde-crosslinked chymotrypsin (GA-CT), which creates insoluble particles. The immobilization efficiency was determined by absorbance spectrophotometry and found to be 96% of the total amount of chymotrypsin added. Different immobilization (i.e., crosslinking) conditions such as buffer composition/pH and initial mass of CT during crosslinking as well as different storage conditions such as temperature, time and humidity for the GA-CT particles were evaluated by comparing capillary electrophoretic (CE) peptide maps of protein standards digested with the particles. The GA-CT particles were used to digest BSA as an example of a large folded protein that needs denaturation prior to digestion, and casein-fluorescein isothiocyanate (FITC) as an example of a small, labeled substrate to test enzyme activity in the presence of substrate-bound fluorescent groups. Peptide mapping of digests from GA-CT particles was achieved by CE with ultraviolet (UV) absorbance or laser induced fluorescence (LIF) detection. FITC-labeled casein was digested by GA-CT to the same extent as with free (i.e., soluble) CT. An immobilized enzyme microreactor (IMER) was fabricated by immobilizing CT inside a 250 µm i.d. fused-silica capillary tube pre-treated with 3-aminopropyltriethoxysilane to functionalize the inner walls with amine groups. Glutaraldehyde was reacted with the amine groups and then CT was immobilized by crosslinking to the GA. IMERs based on GA-CT were fabricated using an automated CE system and used to digest BSA, myoglobin, a 9-residue peptide and a dipeptide as examples of large, medium and small substrates. Digests were studied by comparing peptide maps obtained by CE coupled to either UV or mass spectrometric (MS) detection in order to evaluate immobilization conditions as a function of buffer composition/pH and reaction times. A separate study, which used fluorescence microscopy to investigate the extent and location of GA-CT immobilization in the IMER, showed that immobilization only takes place primarily near the capillary walls and that crosslinking does not extend as far into the center of the IMER as had been expected.

A pancreatite crônica é uma desordem complexa, na qual a interação entre fatores ambientais e genéticos resulta na enfermidade. O presente estudo incluiu 148 pacientes com diagnóstico de pancreatite crônica, 110 etilistas crônicos e 297 controles sadios com o objetivo de investigar a frequência de tabagismo e das mutações N34S e P55S do gene SPINK1 e R254W do gene CTRC nesta população. Foi aplicado questionário presencial e realizada reação de sequenciamento para a pesquisa das mutações genéticas, após assinatura do Termo de Consentimento Livre e Esclarecido. Os portadores de pancreatite crônica possuíam etiologia alcoólica em 74% das vezes e idiopática em 26%. A pancreatite alcoólica apresentou-se de maneira distinta da pancreatite crônica idiopática, sendo que o primeiro grupo é composto por maior prevalência do gênero masculino (88,18% versus 34,21%), por maior média de idade (55,64 anos versus 45,20 anos), menor frequência de caucasianos (63,89% versus 84,21%), menor escolaridade (23,30% concluíram ensino médio ou superior versus 57,89%) e maior frequência de repercussões da doença, como diarréia (54,21% versus 24,24%), emagrecimento (56,07% versus 24,24%), diabete melito (57,94% versus 36,36%) e ocorrência de pseudocistos pancreáticos (31,78% versus 12,12%), repercussões estas que não foram acompanhadas de maior frequência de alterações morfológicas, como calcificações pancreáticas ou dilatação do ducto pancreático principal. A frequência de tabagismo foi significativamente maior em pacientes com pancreatite crônica alcoólica do que em etilistas sem pancreatite crônica, podendo ser considerado cofator de risco para o desenvolvimento da pancreatite crônica entre alcoolistas (p = 0,002); a frequência da mutação N34S do gene SPINK1 em pacientes com pancreatite crônica foi de 3,38%, maior do que a frequência de 0,49% encontrada nos grupos controle (p = 0,016); a frequência de 2,03% da mutação P55S do gene SPINK1 e a frequência de 0,67% da mutação R254W do gene CTRC, encontradas nos pacientes com pancreatite crônica, não diferiram estatisticamente quando comparadas às frequências, de 0,49% de ambas mutações, encontradas nos grupos controle. (p = 0,120 e 0,751). Pela investigação da associação de tabagismo e da mutação N34S do gene SPINK1 com as características clínicas e morfológicas da pancreatite crônica, verificou-se que a mutação N34S não se associou a maior gravidade da apresentação clínica ou morfológica da pancreatite crônica; no entanto o tabagismo associou-se a maior frequência de diabete melito entre os portadores de pancreatite crônica. Concluiuse que o tabagismo e a mutação N34S do gene SPINK1 podem ser considerados cofatores de risco para o desenvolvimento da pancreatite crônica / Chronic pancreatitis is a complex disorder in which the interaction between environmental and genetic factors results in the disease. This study included 148 patients with chronic pancreatitis, 110 chronic alcoholics and 297 healthy controls in order to investigate the frequency of smoking and N34S and P55S mutation of SPINK1 gene and R254W of CTRC gene in this population. A questionnaire was applied and gene sequencing was done, after having the Informed Consent Statement. Those with chronic pancreatitis had alcoholic etiology in 74% of cases and idiopathic in 26%. Alcoholic pancreatitis presented in a distinct way of idiopathic chronic pancreatitis. The first group is composed of a higher prevalence of males (88.18% versus 34.21%), by higher mean age (55.64 years versus 45.20 years), lower frequency of Caucasians (63.89% versus 84.21%), lower education (23.30% completed secondary or higher education versus 57.89%) and worst impact from the disease such as diarrhea (54.21% versus 24.24%), weight loss (56.07% versus 24.24%), diabetes mellitus (57.94% versus 36.36%) and occurrence of pancreatic pseudocysts (31.78% versus 12 , 12%). These effects were not accompanied by increased frequency of morphological changes, such as pancreatic calcifications or dilation of the main pancreatic duct. The frequency of smoking was significantly higher in patients with alcoholic pancreatitis than in alcoholics without chronic pancreatitis, therefore tabagism may be considered as a cofactor for the development of chronic pancreatitis among alcoholics (p = 0.002); the frequency of N34S mutation of SPINK1 gene in patients with chronic pancreatitis was 3.38%, higher than the rate of 0.49% found in the control groups (p = 0.016); the frequency of 2.03% of the P55S mutation of SPINK1 gene and the frequency of 0.67% of the CTRC gene R254W mutation found in patients with chronic pancreatitis were not statistically different when compared to the frequencies of 0.49% of both mutations, found in the control groups. (p = 0.120 and 0.751) For the investigation of the association of smoking and N34S mutation of SPINK1 gene with the clinical and morphological features of chronic pancreatitis, it was noticed that the N34S mutation did not determine a greatest severity in the presentation of chronic pancreatitis, however smoking was associated with a higher frequency of diabetes mellitus in patients with chronic pancreatitis. It was concluded that smoking and the N34S mutation of SPINK1 gene are positively correlated with chronic pancreatitis

Philosophiae Doctor - PhD / Given the significant disease burden caused by human coronaviruses, the discovery of an effective antiviral strategy is paramount, however there is still no effective therapy to combat infection. This thesis details the in silica exploration of ligand libraries to identify candidate lead compounds that, based on multiple criteria, have a high probability of inhibiting the 3 chymotrypsin-like protease (3CUro) of human coronaviruses. Atomistic models of the 3CUro were obtained from the Protein Data Bank or theoretical models were successfully generated by homology modelling. These structures served the basis of both structure- and ligand-based drug design studies. Consensus molecular docking and pharmacophore modelling protocols were adapted to explore the ZINC Drugs-Now dataset in a high throughput virtual screening strategy to identify ligands which computationally bound to the active site of the 3CUro . Molecular dynamics was further utilized to confirm the binding mode and interactions observed in the static structure- and ligand-based techniques were correct via analysis of various parameters in a IOns simulation. Molecular docking and pharmacophore models identified a total of 19 ligands which displayed the potential to computationally bind to all 3CUro included in the study. Strategies employed to identify these lead compounds also indicated that a known inhibitor of the SARS-Co V 3CUro also has potential as a broad spectrum lead compound. Further analysis by molecular dynamic simulations largely confirmed the binding mode and ligand orientations identified by the former techniques. The comprehensive approach used in this study improves the probability of identifying experimental actives and represents a cost effective pipeline for the often expensive and time consuming process of lead discovery. These identified lead compounds represent an ideal starting point for assays to confirm in vitro activity, where experimentally confirmed actives will be proceeded to subsequent studies on lead optimization.

No description available.