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Papain enzymatic hydrolysis

Specimens for assay were prepared by suspending 500 mg of lyophilized brain in 50 ml of the buffer-papain mixture and hydrolyzing overnight at 37° C. The solution was then autoclaved for 10 minutes. This procedure yielded higher results than autolysis or prolonged enzymatic hydrolysis. After centrifuging off the debris, 0.5, 1.5, and 2.5 ml of the supernatant were used for assay. This represents 1, 3, and 5 mg of the original brain tissue per milliliter of final medium. [Pg.208]

Due to the relative stability of the niacin vitamers, either acid or alkaline hydrolysis can be used to convert nicotinamide to nicotinic acid for quantitation of both vitamers as nicotinic acid (9,44). Acid hydrolysis is used to quantitate biologically available niacin. Alkaline hydrolysis releases both the biologically available and the unavailable vitamers and provides an estimate of the total niacin content. Because alkaline hydrolysis is much faster than acid hydrolysis, the latter is usually supplemented with enzymatic hydrolysis. The most common enzymes are takadiastase, papain, and clarase. On occasion, organic solvents such as methanol have been used to extract free nicotinic acid. [Pg.430]

Endogenous biotin in foods is predominately protein bound and is relatively stable (180). Consequently it can be extracted under fairly harsh conditions, e.g., autoclaving in 4 M sulfuric acid for 2 hours at 120°C. Enzymatic hydrolysis with papain will also release biotin from proteins (181). Potential sample-cleanup procedures include adsorption on charcoal and/or ion-exchange chromatography (182,183). [Pg.453]

Recently a simplified process was developed for incorporating l-methionine directly into soy proteins during the papain-catalyzed hydrolysis (21). The covalent attachment of the amino acid requires a very high concentration of protein and occurs through the formation of an acyl-enzyme intermediate and its subsequent aminolysis by the methionine ester added in the medium. From a practical point of view, the main advantage of enzymatic incorporation of amino acids into food proteins, in comparison with chemical methods, probably lies in the fact that racemic amino acid esters such as D,L-methionine ethyl ester can be used since just the L-form of the racemate is used by the stereospecific proteases. On the other hand, papain-catalyzed polymerization of L-methio-nine, which may occur at low protein concentration (39), will result in a loss of methionine because of the formation of insoluble polyamino acid chains greater than 7 units long. [Pg.153]

Versari, A., Menard, R., and Lortie, R., Enzymatic hydrolysis of nitrides by an engineered nitrile hydratase (papain Glnl9Glu) in aqueous-organic media, Biotech. Bioeng., 79 9-14, 2002. [Pg.91]

The determination of total Be as PN was collaboratively studied by 12 laboratories in a comparative study (Bergaentzle et al. 1995) all the Be vitamers in food were dephosphorylated with acid phosphatase, after which PM was deaminated to PL in the presence of glyoxylic acid and ferrous sulfate. The PL was reduced to PN by sodium borohydride and the total vitamin Be content was determined as one vitamer (PN) by HPLC. Another study reported that the most suitable extraction procedure for determining endogenous total vitamin Be in food (meat, fish, milk) was treatment with 0.1 M hydrochloric acid at 120 °C for 30 min, followed by enzymatic hydrolysis with p-glucosidase alone or in combination with acid phosphatase. Some authors (Ndaw et al. 2000) have recommended the extraction procedure consisting of incubation with papain, a-amylase and phosphatase for 18 h at 37 °C, and compared this protocol with four other extraction protocols involving combinations with acid and enzymatic hydrolysis. [Pg.234]

One of the most desired transformations is a hydrolysis of above substances resulting in free lysergic acid, the substrate for many semisynthetic preparations. Chemical hydrolysis of its derivatives gives low yields (50-65%). Fermentative production of lysergic acid is somehow complicated. Enzymatic hydrolysis of peptide alkaloids is still impracticable. Common proteolytic enzymes (papain, subtilisin, chymotrypsin, termolysin) do not attack peptidic bond in ergokryptine... [Pg.250]

Then a solution of papain (200ml of 0.1% solution of papain per 1kg of material) is added. Enzymatic hydrolysis of proteins is carried out for 20-40h. Every 6-8 h the pH must be adjusted to 6-7 (to optimize enzyme activity). The HA mixture is purified by ultrafiltration and precipitation with 96% ethanol. The final product, sodium hyaluronate, is dried by lyophilization and the precipitate is then dissolved in a water-alcohol mixture containing 40% ethanol. The final purification of hyaluronan is performed by membrane filtration of a solution containing 30-50% ethanol. [Pg.81]

Claradiastase and trypsin in phosphate buffer have been used for hydrolysis of sample matrix for the determination of supplemental folic acid (27). Jacoby and Henry (26) further modified the method of Hoppner and Lampi (41) for folic acid by HPLC, in which the folic acid added to infant formulas and liquid medical nutritionals is quantitatively extracted with the aid of bacterial protease and papain. One disadvantage of the enzymatic extraction method was the large number of UV-absorbing compounds that are formed during enzymatic hydrolysis. These can interfere in the quantitation of the folate peaks. Thus, addition of a-amylase and protease to enhance extraction has not been common practice for methods involving HPLC. However, Pfeiffer et al. (13) suceessfiilly used triple-enzyme treatment prior to HPLC analysis with a purification method based on affinity chromatography. [Pg.315]

Samples, in either 0.1 N HCl or 0.1 AH2SO4, were autoclaved for 30 min and then subjected to enzymatic hydrolysis with either Taka-diastase or papain. The filtrate was then chromatographed. [Pg.382]

Meat was homogenized in 0.1 M HCl, heated at 100°C for 1 h, cooled, and adjusted to a pH of 4.5 to 5. The mixture was then subjected to enzymatic hydrolysis with mylase 100 and papain for 4 h at 45 to 50°C. To cleave thiamine to 4-methyl-5-(2-hydroxyethyl)thiazole, NaHSOs or Na2S03 was added, the pH was readjusted to 4 to 5, and the mixture was again heated at 100°C for 2 h. After the addition of trichloroacetic acid (TCA), the mixture was chilled and filtered. The filtrate was adjusted to a pH of 11 to 12 and then extracted with chloroform, which was evaporated to dryness. The residue was taken up in 1 mL internal standard solution and the latter was concentrated to 0.5 mL. The resulting sample was stored for analysis. [Pg.395]

The proposed methods are based on spectrometric, chromatographic, and proteinbinding techniques. As biotin occurs in food both in free form and covalently bound to proteins, in many methods it is necessary to break these bonds by acid or enzymatic hydrolysis. The former is more frequently used than the latter, since acid treatment converts o-biocytin into o-biotin and allows a total determination of biotin. Enzymatic treatment with papain leaves o-biocytin unchanged and only D-biotin is determined. Despite this, some methods propose enzymatic hydrolysis rather than acid hydrolysis because it does not induce any degradation of biotin. [Pg.413]

Enzymatic hydrolysis of proteins is an attractive alternative to the hydrolytic procedures and has been used to avoid destruction of tryptophan (174). A mixture of proteolytic enzymes, such as chymo-trypsin, thermolysin, papain, leucine aminopeptidase and pronase has been used (135, 192, 353). Upon completion of the enzymatic hydrolysis of the protein, the hydrolyzate is rendered free of proteolytic enzymes by precipitation and centrifugation and the extract directly analyzed with the amino acid analyzer. The method however may not be generally valid, because of the possibility of artefacts due to self-digestion of the enzymes used. [Pg.374]

Either acid or alkaline hydrolysis can be applied, converting nicotinamide to nicotinic acid. Alkaline hydrolysis releases also the unavailable vitamers providing the estimation of the total niacin content. Acid hydrolysis, instead, is slower than alkaline hydrolysis therefore the former is usually coupled with enzymatic digestion by using takadiastase, papain, and clarase. Extraction with water and dilute sulfuric or hydrochloride acid has been applied to release the vitamers from the matrix without degrading nicotinamide [598]. [Pg.626]

Pantothenic acid occurs in foods both in the free form and bonded to coenzyme (CoA) or acyl carrier protein (ACP) therefore hydrolysis is needed to extract it totally. Since it is degraded by acid and alkaline hydrolysis, only an enzymatic digestion can be applied. Enzyme hydrolysis with papain, diastase, clarase, takadiastase, intestinal phosphatase, pigeon liver pantetheinase, or combination of them has been used. [Pg.628]

Acid hydrolysis with HCl at 121°C for 30 min Enzymatic digestion with amylase, papain, acid phosphatase with Gh for 1 h filtration... [Pg.631]

It should be noted that ascorbic acid is more stable at pH 4-5 than at pH 7, at which the folacin vitamers are more stable. Additional protection from oxidation can be achieved by degassing the extraction solution with an inert gas, such as helium. Homogenization is followed immediately by protein precipitation and release of bound folacin vitamers. This can be accomplished by mild acidification, heating, addition of organic compounds such as trichloroacetic acid, and/or enzymatic (e.g., papain) hydrolysis. The specific conditions used for homogenization and protein precipitation are dictated by the food matrix and the expected profile of folacin vitamers. [Pg.442]

Enzymatic gelation of partially heat-denatured whey proteins by trypsin, papain, pronase, pepsin, and a preparation of Streptomyces griseus has been studied (Sato et al., 1995). Only peptic hydrolysate did not form a gel. The strength of the gel depended on the enzyme used and increased with increasing DH. Hydrolysis of whey protein concentrate with a glutamic acid specific protease from Bacillus licheniformis at pH 8 and 8% protein concentration has been shown to produce plastein aggregates (Budtz and Nielsen, 1992). The viscosity of the solution increased dramatically during hydrolysis and reached a maximum at 6% DH. Incubation of sodium caseinate with pepsin or papain resulted in a 55-77% reduction in the apparent viscosity (Hooker et al., 1982). [Pg.40]


See other pages where Papain enzymatic hydrolysis is mentioned: [Pg.49]    [Pg.243]    [Pg.251]    [Pg.416]    [Pg.424]    [Pg.460]    [Pg.24]    [Pg.292]    [Pg.91]    [Pg.92]    [Pg.298]    [Pg.310]    [Pg.93]    [Pg.1337]    [Pg.17]    [Pg.56]    [Pg.236]    [Pg.20]    [Pg.308]    [Pg.788]    [Pg.98]    [Pg.208]    [Pg.86]    [Pg.71]    [Pg.23]    [Pg.288]    [Pg.68]    [Pg.178]    [Pg.205]    [Pg.208]    [Pg.652]   
See also in sourсe #XX -- [ Pg.97 ]




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