1 gram, powder
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|Content:||1 gram, powder|
|Storage Temperature:||Below -10oC|
|Formulation:||In powder form|
|Stability:||Minimum 1 year at < -10oC. Check vial for details.|
|Synonyms:||subtilisin; subtilisin A|
|Expression:||Purified from Bacillus licheniformis|
|Specificity:||Hydrolysis of proteins with broad specificity for peptide bonds, and a preference for a large uncharged residue in P1. Hydrolyses peptide amides.|
|Specific Activity:||> 10 U/mg of protein; (40oC, pH 8.0 on casein)|
|Unit Definition:||One Unit will hydrolyse casein to produce colour equivalent to one μmole (181 µg) of tyrosine per minute at pH 7.0 at 40oC (colour by Folin-Ciocalteu reagent).|
|Application examples:||This enzyme is recommended for use in the Megazyme Total Dietary Fiber test method and AOAC INTERNATIONAL Total Dietary Fiber analytical procedures.|
High purity Protease (Subtilisin A from Bacillus licheniformis) (Powder) for use in research, biochemical enzyme assays and in vitro diagnostic analysis.
For use in Megazyme Total Dietary Fiber test method.
See analytical enzymes for our other enzyme products.
Bui, L. T. T. & Small, D. M. (2007). Journal of Food Science, 72(5), C283-C287.
The folate contents of 26 commercial noodle samples were investigated. The impact of ingredients, pH, and cooking on folate content was studied for the 3 predominant styles of noodles: white salted, yellow alkaline, and instant. Some variability was found in the proportion of folate present in the free form and the noodles generally had low total folate contents. The pH values of the samples covered a wide range, varying from 3.7 to 10.3; however, the results did not provide strong evidence for a relationship between pH and folate content for any of the noodle styles studied. Higher folate levels were typically found in yellow alkaline samples compared to white salted and instant noodles. The storage of noodles in dry or moist forms did not appear to influence total folate contents, and subsequent losses during cooking depended upon the time of exposure to elevated temperatures. The enzymatic treatment of samples was particularly important for cooked noodles, indicating that folates were bound or entrapped during this process.Hide Abstract
Chandra-Hioe, M. V., Bucknall, M. P. & Arcot, J. (2017). Food Chemistry, 234, 365-371.
This study compares enzymatic treatments to release folic acid (FA) and endogenous 5-methyltetrahydrofolate (5-MTHF) from infant milk formulae with enzyme-free heat extraction. The limits of detection and quantitation of FA were 1.4 ng/mL and 3.1 ng/mL, respectively; 7.5 ng/mL and 16.2 ng/mL for 5-MTHF. Absolute mean recoveries were 85% (FA) and 95% (5-MTHF). The RSD of the within-run variability was 6% and the inter-day variability was 8%. Averaged measurements of FA and 5-MTHF in SRM-1849a were within the certified value range. Analysed folate levels in three brands were greater than label values, because of inherently high 5-MTHF occurring in samples. The results indicate that enzyme-free heat treatment prior to UPLC–MS/MS analysis gives better sensitivity and reduces chromatographic interferences for the determination of FA and 5-MTHF in milk formulae than enzymatic treatments. Enzyme-free heat treatment is more compatible with UPLC–MS/MS than folate extraction techniques involving the addition of enzymes to milk.Hide Abstract
Cheung, R. H. F., Hughes, J. G., Marriott, P. J. & Small, D. M. (2009). Food Chemistry, 112(2), 507-514.
A simple, rapid procedure, using capillary zone electrophoresis (CZE), that can efficiently measure added folic acid in fortified instant fried noodles has been developed and validated. Optimum separation of folic acid was obtained on a 72 cm × 75 µm capillary using 8 mM phosphate-12 mM borate run buffer with 5% MeOH at pH 9.5, temperature of 30°C and voltage of 28 kV. The extracts were introduced into the capillary via electrokinetic injection and the folic acid monitored at 214 nm. For quantification purposes, nicotinic acid was added as internal standard to all samples. Under these conditions the analysis required approximately 12 min. Good results were obtained for different analytical parameters including linearity, accuracy and precision. The limit of detection was calculated to be 5.3 mg/L. Prior to CZE determination, noodle samples were homogenized in the buffer solution for 1 h followed by treatment with α-amylase solution for 1 h at 65°C or protease solution for 4 h at 37°C. The enzyme solution was added at a concentration of 25 mg/L and then adjusted to pH 7.0. Using standard addition to eliminate the effect of sample matrix interference, results showed that a higher and more efficient recovery of added folic acid could be obtained when using α-amylase. During the four main stages of instant fried noodle manufacturing (dough crumbs, cut sheets, steaming and frying) folic acid was found to be stable with recoveries of 96–103%.Hide Abstract
Iwatani, Y., Arcot, J. & Shrestha, A. K. (2003). Journal of Food Composition and Analysis, 16(1), 37-48.
The undeconjugated and total folate contents of 22 vegetables commonly available in Australia were assayed with Lactobacillus casei after preliminary digestion with chicken pancreas. The effect of conjugate type and extraction technique on the total folate content of two of the vegetables was also investigated. In two test samples, spinach and Chinese broccoli, deconjugation with chicken pancreas gave slightly higher, but statistically not different (P<0.05), folate values compared to human plasma. Tri-enzyme extraction gave lower folate value compared to single-enzyme extraction, the result was significant (P<0.05) only in Chinese broccoli. Single-enzyme extraction using chicken pancreas was therefore used for extraction of folate in all vegetables. The range of undeconjugated and total folate in vegetables was 27–322 and 68–425 µg total folate/100 g (wet weight), respectively. The average undeconjugated to total folate ratio in 22 vegetables was 0.60, ranging from 0.19 to 0.89. Chinese flowering cabbage contained the highest level of total folate at 425 µg /100 g. Among the rest of the 21 vegetables, four vegetables contained more than 300 μg, five contained 200–300 µg, 10 contained 100–200 µg, and two contained less than 100 µg folate/100 g.Hide Abstract