Antibody-mediated targeting of alpha-1,4-glucosidase-albumin polymers to rat hepatocytes. A model for enzyme therapy.
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ABSTRACT:
SUBMITTER: Poznansky MJ
PROVIDER: S-EPMC1162971 | biostudies-other | 1981 Apr
REPOSITORIES: biostudies-other
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Project description:Abstract The food enzyme glucoamylase (4‐α‐D‐glucan glucohydrolase; EC 3.2.1.3) is produced with the genetically modified Trichoderma reesei strain DP‐Nzh38 by Danisco US Inc. The genetic modifications do not give rise to safety concerns. The food enzyme is free from viable cells of the production organism and its DNA. The food enzyme is intended to be used in distilled alcohol production, starch processing for glucose syrup production, baking and brewing processes. Since residual amounts of total organic solids (TOS) are removed by distillation and by purification steps applied during the production of glucose syrups, consequently, dietary exposure was not calculated for these uses. Based on the maximum use levels recommended for baking and brewing processes and individual data from the EFSA Comprehensive European Food Consumption Database, dietary exposure to the food enzyme–TOS was estimated to be up to 5.8749 mg TOS/kg body weight per day. The toxicity studies were carried out with another glucoamylase from T. reesei (strain DP‐Nzh49) considered by the Panel as a suitable substitute. Genotoxicity tests did not raise safety concern. The systemic toxicity was assessed by means of a repeated dose 90‐day oral toxicity study in rats. The Panel identified no observed adverse effect level (NOAEL) at the highest dose tested of 1,149 mg TOS/kg body weight (bw) per day resulting in a margin of exposure of at least 195. Similarity of the amino acid sequence to those of known allergens was searched for and one match was found. The Panel considered that, under the intended conditions of use, the risk of allergic sensitisation and elicitation reactions by dietary exposure cannot be excluded, but the likelihood for this to occur is considered to be low. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.
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Project description:Abstract The food enzyme glucan 1,4‐α‐glucosidase (4‐α‐d‐glucan glucohydrolase; EC 3.2.1.3) is produced with the non‐genetically modified Rhizopus arrhizus strain AE‐G by Amano Enzyme Inc. The food enzyme is free from viable cells of the production organism. The applicant proposed the use of the food enzyme in baking processes, coffee processing and manufacture of enzymatically modified dairy ingredients (EMDI). The Panel considered only the baking processes as the relevant intended use of this food enzyme. Dietary exposure to the food enzyme–total organic solids (TOS) was estimated to be up to 0.94 mg TOS/kg body weight (bw) per day in European populations. Genotoxicity tests did not raise a safety concern. The systemic toxicity was assessed by a repeated dose 90‐day oral toxicity study in rats. The Panel identified a no observed adverse effect level of 1,868 mg TOS/kg bw per day, the highest dose tested, which when compared with the estimated dietary exposure, resulted in a margin of exposure of at least 1,987. A search for the similarity of the amino acid sequence of the food enzyme to known allergens was made and one match was found. The Panel considered that under the intended conditions of use the risk of allergic reactions by dietary exposure cannot be excluded, but the likelihood is low. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns when used in baking processes under the intended conditions of use.
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Project description:The food enzyme glucan 1,4-α-glucosidase (4-α-d-glucan glucohydrolase EC 3.2.1.3) is produced with the genetically modified Aspergillus niger strain NZYM-BE by Novozymes A/S. The genetic modifications do not give rise to safety concerns. The food enzyme was free from viable cells of the production organism and its DNA. The food enzyme is intended to be used in six food manufacturing processes, namely starch processing for the production of glucose syrups and other starch hydrolysates, distilled alcohol production, brewing processes, baking processes, cereal-based processes, and fruit and vegetable processing for juice production. Since residual amounts of total organic solids (TOS) are removed by distillation and by the purification steps applied to produce glucose syrups, dietary exposure was not calculated for these two food processes. For the remaining four processes, dietary exposure to the food enzyme-TOS was estimated to be up to 7.7 mg TOS/kg body weight (bw) per day in European populations. Genotoxicity tests did not raise a safety concern. The systemic toxicity was assessed by means of a repeated dose 90-day oral toxicity study in rats. The Panel identified a no observed adverse effect level of 3,795 mg TOS/kg bw per day, the highest dose tested, which when compared with the estimated dietary exposure, results in a margin of exposure above 490. Similarity of the amino acid sequence of the food enzyme to those of known allergens was searched for and one match found. The Panel considered that, under the intended conditions of use (other than distilled alcohol production) the risk of allergic sensitisation and elicitation reactions by dietary exposure cannot be excluded, but the likelihood for this to occur is considered to be low. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.
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Project description:Lysosomal storage disorders (LSDs) are caused by defective enzyme activities in lysosomes, characterized by the accumulation of sphingolipids, glycolipids, oligosaccharides, mucopolysaccharides, the oxidation products of cholesterol, and other biological substances. A growing number of clinical studies have suggested the enhanced efficacy of existing therapies, including enzyme replacement therapy, which is effective when it is initiated during the presymptomatic period. Thus, the identification of disease-affected individuals by newborn screening has been considered an effective platform. Previous studies have suggested that the discrimination of infantile-onset Pompe disease (IOPD) requires multi-step examination of GAA enzyme activity using the fluorometric technique. In sharp contrast, the MS/MS-based technique can identify the population of IOPD and the pseudodeficiency alleles of the GAA enzyme [Liao HC et al. Clin Chem (2017) in press; doi: http://dx.doi.org/10.1373/clinchem.2016.269027]. To determine whether MS/MS-based assay can identify these two populations in Japanese neonates, we first performed a validation study of this assay using flow-injection analysis (FIA)-MS/MS and liquid chromatography (LC)-MS/MS followed by examination of GAA enzyme activity in our population. By minimizing the effect of substrate-derived in-source decomposition products, the activities of 6 LSD enzymes were quantified in FIA-MS/MS and LC-MS/MS. The mean value of GAA activity with IOPD, pseudodeficiency alleles, and healthy controls by FIA-MS/MS were 1.0 ± 0.3 μmol/h/L (max, 1.3; min, 0.7; median, 1.2; n = 3), 2.7 ± 0.7 μmol/h/L (max, 4.5; min, 1.5; median, 2.5; n = 19), and 12.9 ± 5.4 μmol/h/L (max, 29.6; min, 2.5; median, 11.0; n = 83), respectively. These results suggest that the population of GAA with pseudodeficiency alleles has approximately 20% of GAA enzyme activity compared to controls, providing the preliminary evidence to estimate the cut-off values in the Japanese population using this technique.
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Project description:Nigella sativa L. (Ranunculaceae), commonly referred to as black seeds or black cumin, is used in popular medicine (herbal) all over the world for the treatment and prevention of several diseases, including diabetes. This study aims to investigate the inhibitory effect of N. sativa extracts and fractions against the activities of intestinal α-glucosidase and pancreatic α-amylase in vitro, and to explain the inhibitory effect of these fractions against these enzymes by identifying their active compounds responsible for this effect and determine their modes of inhibition. To do so, N. sativa hexane and acetone extracts were prepared and analyzed by GC-MS and HPLC-DAD, respectively. The hexane extract was further fractioned into eight different fractions, while the acetone extract generated eleven fractions. The extracts as well as the resulting fractions were characterized and evaluated for their potential in vitro antidiabetic activity using intestinal α-glucosidase and pancreatic α-amylase inhibitory assays in vitro. Hexane extract and fractions were less active than acetone extract and fractions. In the case of intestinal α-glucosidase activity, the acetone fraction SA3 had a high inhibitory effect on intestinal α-glucosidase activity with 72.26 ± 1.42%, comparable to the effect of acarbose (70.90 ± 1.12%). For the pancreatic α-amylase enzymatic inhibitory assay, the acetone fractions showed an inhibitory capacity close to that for acarbose. In particular, the SA2 fraction had an inhibitory effect of 67.70 ± 0.58% and was rich in apigenin and gallic acid. From these fractions, apigenin, (-)-catechin, and gallic acid were further characterized for their inhibitory actions. IC50 and inhibition mode were determined by analyzing enzyme kinetic parameters and by molecular modeling. Interestingly, (-)-catechin showed a possible synergistic effect with acarbose toward α-glucosidase enzyme inhibition, whereas apigenin showed an additive effect with acarbose toward α-amylase enzymatic inhibition. Furthermore, we studied the toxicity of N. sativa hexane and acetone extracts as well as that of acetone fractions. The result of acute toxicity evaluation demonstrated that N. sativa extracts were nontoxic up to a concentration of 10 g/kg, except for fraction SA3. Taken together, these results indicate that N. sativa extracts and/or derived compounds could constitute promising nutraceuticals for the prevention and treatment of type 2 diabetes mellitus.
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