Evaluation of the proteolysis degree with the o-phthalaldehyde/N-acetyl-L-cysteine reagent

Medina-Hernández, M.J.; Domingo, E. Bonet; Camañas, R. M. Villanueva; Garcı́a-Alvarez-Coque, M.C.

doi:10.1007/bf00322787

Cited by 12 publications

(3 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The content of free amino groups of casein hydrolysates or casein plasteins on protein basis was measured by the o-phthaldialdehyde (OPA) assay used by Church et al [7] and Hernández et al [11] with some modifications. The final solution of OPA was made by combining the following reagents and diluting them to 100 mL with boric-borate buffer: boric-borate buffer of pH 9.5 consisting 0.4 mol·L −1 boric acid and 0.3 mol·L…”

Section: The Content Of Free Amino Groups and Degree Of Hydrolysismentioning

confidence: 99%

Preparation and radical scavenging activity of papain-catalyzed casein plasteins

Zhao

2010

Dairy Sci. Technol.

View full text Add to dashboard Cite

-The aim of this study was to prepare papain-catalyzed casein plasteins and to demonstrate the influence of the plastein reaction on the radical scavenging activity. Casein was initially hydrolyzed with papain under selected conditions to give a degree of hydrolysis of 9.6%. The casein hydrolysates were then subjected to papain-catalyzed plastein reaction to prepare casein plasteins. The formation of plasteins in the prepared casein plasteins was confirmed by size exclusion chromatography. The optimal conditions for the plastein reaction, determined by response surface methodology using the decrease of free amino groups in the casein plasteins as the response variable, were as follows: papain addition level was fixed at 500 U·g −1 proteins, reaction temperature 30°C, concentration of casein hydrolysates 50% and reaction time 5.6 h. Six different casein plasteins were prepared and the radical scavenging activity on two radicals, 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS), was evaluated by the Trolox equivalent antioxidant capacity (TEAC). Analysis showed that all casein plasteins had improved radical scavenging activities. Compared to casein hydrolysates, the scavenging activity of the casein plasteins on DPPH radical had a seven-or ninefold increase, as TEAC increased from 10.45 to 73.41 or 90.31 mmol·g −1 proteins, while a onefold increase was detected on ABTS + (TEAC increased from 8.33 μmol·g −1 to 15.09 or 16.45 μmol·g −1 proteins). The results of this study clearly showed that the papain-catalyzed plastein reaction could be applied to prepare casein antioxidant peptides with higher activity, and that the plastein reaction may have a new application in dairy science.casein / plastein reaction / papain / radical scavenging activity / antioxidant 摘要 -酪蛋白类蛋白物的木瓜蛋白酶法制备及其自由基清除活性○ 本研究利用木瓜蛋白酶催化制备酪蛋白类蛋白物，证明类蛋白反应影响酪蛋白类蛋白物的自由基清除活性○ 首先，在选定的条件下用木瓜蛋白酶水解酪蛋白，制备出水解度为 9.6% 的酪蛋白水解物; 然后，酪蛋白水解物进行类蛋白反应制备酪蛋白类蛋白物，并且用排阻色谱证实所制备的酪蛋白类蛋白物中有类蛋白形成○ 优化的类蛋白反应条件，通过以酪蛋白类蛋白物的游离氨基含量降低为指标、利用响应面法而确定，它们分别是: 木瓜蛋白酶添加量固定为每克蛋白质 500 U，反应温度为 30°C，酪蛋白水解物质量分数为 50%，反应时间为 5.6 h○ 制备 6 个反应程度不同的酪蛋白类蛋白物，并评价它们对 2 个自由基 1,1-二苯基-2-苦基肼 (DPPH)、2,2'-连氮-二 (3-乙基-苯并噻唑啉-6-磺酸)(ABTS) 的 Trolox 等价抗氧化能力 (TEAC)○ 分析结果显示，所有的酪蛋白类蛋白物的自由基清除活性得到改善○ 与酪 Résumé -Préparation de plastéines à partir de la catalyse de caséines par la papaïne et leur activité anti-radicalaire. L'objectif de cette étude était de préparer des plastéines à partir de la catalyse de caséines par la papaïne et de démontrer l'influence de la réaction de formation des plastéines sur l'activité anti-radicalaire. La caséine a été préalablement hydrolysée par la papaïne dans des conditions sélectionnées afin d'obtenir un degré d'hydrolyse de 9,6 %. Les hydrolysats de caséine ont ensuite été soumis à une réaction de catalyse par la papaïne pour préparer les plastéines. La formation des plastéines a été confirmée par chromatographie d'exclusion de taille. Les conditions optimales de la réaction, déterminées par la méthode de surface de réponse ...

show abstract

Section: The Content Of Free Amino Groups and Degree Of Hydrolysismentioning

confidence: 99%

Preparation and radical scavenging activity of papain-catalyzed casein plasteins

Zhao

2010

Dairy Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…A commonly used reagent for the determination of free α- and ε- amino groups is ortho -phthaldialdehyde (OPA), which reacts with primary amino groups in the presence of a thiol compound such as N -acetyl- l -cysteine (NAC) to form a 1-alkylthio-2-alkyl-substituted isoindole. The fluorescent isoindole can absorb light at a wavelength of 340 nm and has been quantified spectrophotometrically [ 1 , 138 , 139 , 140 , 141 , 142 , 143 ].…”

Section: Methodsmentioning

confidence: 99%

Characterization of Conjugates between α-Lactalbumin and Benzyl Isothiocyanate—Effects on Molecular Structure and Proteolytic Stability

2021

View full text Add to dashboard Cite

In complex foods, bioactive secondary plant metabolites (SPM) can bind to food proteins. Especially when being covalently bound, such modifications can alter the structure and, thus, the functional and biological properties of the proteins. Additionally, the bioactivity of the SPM can be affected as well. Consequently, knowledge of the influence of chemical modifications on these properties is particularly important for food processing, food safety, and nutritional physiology. As a model, the molecular structure of conjugates between the bioactive metabolite benzyl isothiocyanate (BITC, a hydrolysis product of the glucosinolate glucotropaeolin) and the whey protein α-lactalbumin (α-LA) was investigated using circular dichroism spectroscopy, anilino-1-naphthalenesulfonic acid fluorescence, and dynamic light scattering. Free amino groups were determined before and after the BITC conjugation. Finally, mass spectrometric analysis of the BITC-α-LA protein hydrolysates was performed. As a result of the chemical modifications, a change in the secondary structure of α-LA and an increase in surface hydrophobicity and hydrodynamic radii were documented. BITC modification at the ε-amino group of certain lysine side chains inhibited tryptic hydrolysis. Furthermore, two BITC-modified amino acids were identified, located at two lysine side chains (K32 and K113) in the amino acid sequence of α-LA.

show abstract

“…There are also many spectrophotometric kinetic assays available including the OPA/NAC assay. Ophthalaldehyde (OPA) reacts with primary amines to form fluorescent residues that absorb at 335 nm (Hernandez et al, 1990). This kinetic assay monitors the change in absorbance due to the release of amino groups.…”

Section: Traditional Methods Of Analysis For Peptides and Proteins Hamentioning

confidence: 99%

The EFFECT OF TEMPERATURE AND EXTRACTION TECHNIQUE ON THE BINDING INTERACTIONS AND HYDROLYSIS OF Β-Lactoglobulin WITH MILK FAT GLOBULE MEMBRANE (MFGM)

Kembel¹

View full text Add to dashboard Cite

Evaluation of the proteolysis degree with the o-phthalaldehyde/N-acetyl-L-cysteine reagent

Cited by 12 publications

References 16 publications

Preparation and radical scavenging activity of papain-catalyzed casein plasteins

Preparation and radical scavenging activity of papain-catalyzed casein plasteins

Characterization of Conjugates between α-Lactalbumin and Benzyl Isothiocyanate—Effects on Molecular Structure and Proteolytic Stability

The EFFECT OF TEMPERATURE AND EXTRACTION TECHNIQUE ON THE BINDING INTERACTIONS AND HYDROLYSIS OF Β-Lactoglobulin WITH MILK FAT GLOBULE MEMBRANE (MFGM)

Contact Info

Product

Resources

About