100 assays (50 of each) per kit
Prices exclude VAT
Available for shipping
|Content:||100 assays (50 of each) per kit|
|Storage Temperature:|| Short term stability: 2-8oC, |
Long term stability: See individual component labels
|Stability:||> 1 year under recommended storage conditions|
|Analyte:||Ammonia, L-Asparagine, L-Glutamine|
|Assay Format:||Spectrophotometer, Microplate|
|Linear Range:||0.2 to 7.0 µg of ammonia, or 0.5 to 50 μg of L-asparagine or L-glutamine per assay|
|Limit of Detection:|| 0.50 mg/L (L-asparagine), |
0.54 mg/L (L-glutamine),
0.06 mg/L (ammonia)
|Reaction Time (min):||~ 20 min|
|Application examples:||Potatoes, potato products, vegetables, cereals and other materials (e.g. biological cultures, samples, etc.).|
|Method recognition:||Novel method|
The L-Asparagine/L-Glutamine/Ammonia test kit is a novel method for the specific, convenient, cost effective and rapid measurement and analysis of L-asparagine, L-glutamine and ammonia as acrylamide precursors in the food industry, or as cell culture media/supernatant components, or in other materials.
Note for Content: The number of manual tests per kit can be doubled if all volumes are halved. This can be readily accommodated using the MegaQuantTM Wave Spectrophotometer (D-MQWAVE).
Browse our complete list of assay test kits.
- Extended cofactors stability. Dissolved cofactors stable for > 1 year at 4oC.
- Very rapid reaction due to use of uninhibited glutamate dehydrogenase
- All enzymes supplied as stabilised suspensions
- Only kit available
- Very cost effective
- All reagents stable for > 2 years after preparation
- Mega-Calc™ software tool is available from our website for hassle-free raw data processing
- Standard included
In vitro study of L-asparaginase enzyme activity by two yeast strains on food matrixes and the relative effect on fungal pathogens growth.
Di Francesco, A. (2022). Frontiers in Bioscience-Elite, 14(1), 6.
Asparagine is one of the precursors of acrylamide and toxic fungal secondary metabolites, both carcinogenic compounds. In the present study, the optimal conditions to deplete asparagine by Aureobasidium pullulans (L1 and L8) from potato and wheat flour matrices were investigated. Through a colorimetric plate-assay with phenol red as indicator dye, both strains demonstrated to be able to produce L-asparaginase from 20°C to 30°C for L1 and only at 20°C for L8 strain starting from 48 h of incubation. The ability of both yeasts to reduce asparagine content in potato and wheat flour was studied by in vitro spectrophotometric assay. Both strains showed a great ability to totally reduce asparagine at 20°C after 15 min of incubation in potato homogenate, conversely in wheat flour, the highest reduction was detected after a longer exposition time (60 min). As known, L1 and L8 diamine asparaginase to aspartic acid. For this reason, both amino acids were tested to verify the antifungal effect against Rhizoctonia solani (Rs1) and Fusarium graminearum (F3) mycelial growth. Asparagine (120 mg/L) increased Rs1 and F3 mycelial growth respectively by 4.4% and 18.9%; conversely, aspartic acid significantly inhibited both respectively by 8.2% and 12.0%.Hide Abstract
Asparagine biosynthesis as a mechanism of increased host lethality induced by Serratia marcescens in simulated microgravity environments.
Gilbert, R., Tanenbaum, N. & Bhattacharya, S. (2022). Heliyon, 8(5), e09379.
While studies have shown an increase in pathogenicity in several microbes during spaceflight and after exposure to simulated microgravity, the mechanisms underlying these changes in phenotype are not understood across different pathogens, particularly in opportunistic pathogens. This study evaluates the mechanism for increased virulence of the opportunistic gram-negative bacterium, Serratia marcescens, in simulated microgravity. Low-shear modeled microgravity (LSMMG) is used in ground-based studies to simulate the effects of microgravity as experienced in spaceflight. Our previous findings showed that there was a significant increase in mortality rates of the Drosophila melanogaster host when infected with either spaceflight or LSMMG treated S. marcescens. Here, we report that LSMMG increases asparagine uptake and synthesis in S. marcescens and that the increased host lethality induced by LSMMG bacteria grown in rich media can be recapitulated in minimal media by adding only aspartate and glutamine, the substrates of asparagine biosynthesis. Interestingly, increased bacterial growth rate alone is not sufficient to contribute to maximal host lethality, since the addition of aspartate to minimal media caused an LSMMG-specific increase in bacterial growth rate that is comparable to that induced by the combination of aspartate and glutamine, but this increase in growth does not cause an equivalent rate of host mortality. However, the addition of both aspartate and glutamine cause both an increase in host mortality and an overexpression of asparagine pathway genes in a LSMMG-dependent manner. We also report that L-asparaginase-mediated breakdown of asparagine is an effective countermeasure for the increased host mortality caused by LSMMG-treated bacteria. This investigation underscores the importance of the asparagine utilization pathway by helping uncover molecular mechanisms that underlie increased mortality rates of a model host infected with microgravity-treated S. marcescens and provides a potential mitigation strategy.Hide Abstract
Effect of added sugars and amino acids on acrylamide formation in white pan bread.
Shen, Y., Chen, G. & Li, Y. (2019). Cereal Chemistry, 96(3), 545-553.
Background and objectives: The products of the Maillard reaction formed from reducing sugars and amino groups are attracting increasing interests as an important dietary antioxidant source. However, acrylamide is also formed during the process, which is a potential carcinogenic substance. The objective of this study was to investigate the effects of various types and amounts of added sugars and amino acids on the formation of acrylamide in white pan bread. Breads were prepared with five sugars (sucrose, glucose, fructose, maltose, and ribose) at three levels (0, 6, and 12 g/100 g flour) and seven amino acids (lysine, alanine, proline, glycine, arginine, threonine, and asparagine) at three levels (0, 0.1 g, and 0.3 g/100 g flour), and the acrylamide content was analyzed by GC‐MS for both the crust and the crumb. Findings: Bread with 6 g/100 g flour fructose had the highest crust acrylamide content of 102.6 μg/kg as compared with other sugars, while the addition of ribose caused the lowest crust acrylamide content (41.0 μg/kg). The addition of asparagine into the bread formula dramatically increased the acrylamide content of crust as expected, while the addition of glycine and proline decreased crust acrylamide. Significant contents of acrylamide were also detected in bread crumbs. Conclusions: Both the type and amount of added sugars and amino acids in bread formulas affect the amount of acrylamide produced in bread products. Significance and novelty: Our study provides a systematic understanding of the effects of added sugars and amino acids on acrylamide formation in wheat bread. This research will benefit industries in developing reduced acrylamide formulas for common bakery products.Hide Abstract
Lecart, B., Jacquet, N., Anseeuw, L., Renier, M., Njeumen, P., Bodson, B., Vanderschuren, H. & Richel, A. (2018). Food Chemistry, In Press.
A new enzymatic methodology is herein proposed to measure free asparagine content in wheat grains and to predict their potential for Maillard reaction products. Our model estimates the acrylamide levels generated during the industrial heat treatment of whole-grain wheat based on free asparagine and glucose measurements. We selected fifteen wheat varieties currently grown in Belgium as benchmark for the present study. While conventional chromatographic methods require a long and tedious multi-step sample preparation, the proposed method takes advantage of being simple and quick. Statistical analysis of free asparagine content indicates that selected wheat varieties can be classified into seven content levels from 0.0149% to 0.0216% of the dry matter. Based on our analysis, the varieties KWS Ozon, Benchmark and Pionier appears to be the most suitable for thermal processing (i.e. cooking applications).Hide Abstract
Weiss, K., Gerstenberger, J., Salzig, D., Mühlebach, M. D., Cichutek, K., Pörtner, R. & Czermak, P. (2015). Engineering in Life Sciences, 15(4), 425-436.
Measles virus (MV) with attenuated pathogenicity has potential as oncolytic agent. However, the clinical translation of this therapy concept has one major hurdle: the production of sufficient amounts of infectious oncolytic MV particles. The current study describes oncolytic MV production in Vero cells grown on microcarrier using serum-free medium. The impact of the number of harvests, cell concentration at infection (CCI), multiplicity of infection (MOI), and temperature on MV production was determined in different production scales/systems (static T-flasks, dynamic spinner, and bioreactor system) and modes (batch, repeated-batch, and perfusion). Cell growth, metabolic, and production kinetics were analyzed. It was found that the number of harvests had the strongest positive impact on MV yield in each production scale, and that high temperatures affected MV yield adversely. Moderate MV titers were produced in T- and spinner flasks at 37°C (~107 TCID50 mL-1, where TCID50 is tissue culture infective doses 50%), but stirred tank reactor (STR) MV production at 37°C yielded up to 10 000-fold lower MV titers. In contrast, at lower temperatures (32°C, 27°C), 1.4 × 107 TCID50 mL-1, were achieved in the STR. Variations in MOI and CCI had almost no influence on MV production yield. The current study improves oncolytic MV production process understanding and identifies process bottlenecks for large-scale production.Hide Abstract