The Quantification of Protein Amino Groups by the Trinitrobenzenesulfonic Acid Method: A Reexamination

Cayot, Philippe; Tainturier, G.

doi:10.1006/abio.1997.2161

Cited by 164 publications

(112 citation statements)

References 77 publications

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“…Measurement of the S-K and H-K polymers with poly-l-lysine (Sigma, St Louis, MO, USA) used as a standard were done with 2,6-dinitro-4-trifluoromethylbenzenesulfonate (Pierce, Rockford, IL, USA) as previously described. 33,34 Preparation of liposomes Preparation of the liposome:plasmid complexes have been previously described. 8,32 In brief, DH5 bacteria (Life Technologies, Gaithersburg, MD, USA) containing the plasmids were grown in Superbroth to mid-log phase.…”

Section: ) H-s (19 Mer)-s-h-s-h-s-h-s-h-s-g-s-h-s-h-s-h-s-h-s]; and (mentioning

confidence: 99%

Co-polymer of histidine and lysine markedly enhances transfection efficiency of liposomes

et al. 2000

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Development of nonviral delivery systems is progressing toward a transfection efficiency sufficient to affect metabolic and neoplastic diseases in humans. Nevertheless, inadequate transfection efficiency of target cells with current nonviral systems still limits the utility of this therapy. In the current study, we have determined that a co-polymer of histidine and lysine (H-K) enhances the transfection efficiency of liposomes, a leading nonviral system. We found that in the absence of serum, the addition of this polymer increased transfection as much as 10-fold in comparison with the lipo-

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Section: ) H-s (19 Mer)-s-h-s-h-s-h-s-h-s-g-s-h-s-h-s-h-s-h-s]; and (mentioning

confidence: 99%

Co-polymer of histidine and lysine markedly enhances transfection efficiency of liposomes

et al. 2000

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“…The resulting trinitrophenyl (TNP) derivatives had a UV absorption with a high molar extinction coefficient at 340 nm. This method was further examined and modified through the years and widely applied to determine free amino groups in proteins (65)(66)(67)(68)(69)(70). Kakade and Liener (66) introduced an extraction step which removed both excess unreacted TNBS and TNP-α-amino derivatives.…”

Section: Ultra Violet Spectrophotometrymentioning

confidence: 99%

Dissolution of Gelatin Capsules: Evidence and Confirmation of Cross-Linking

Lu¹,

Shah²

2017

Dissolution Technol.

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Cross-linking is a common problem in the dissolution of gelatin capsules. Cross-linking is characterized by a bridge across the peptide backbone of the gelatin molecule which creates water insoluble membranes or pellicles during dissolution testing. The chemical covalent bonding between gelatin chains is typically triggered by catalytic amounts of aldehyde and/or from exposure to high temperature and humidity. Cross-linking gelatin capsules results in a slower release of the drug or no release at all in common dissolution media. If the gelatin capsule dissolution fails acceptance criteria due to evidence of cross-linking, the US Pharmacopeia allows the use of enzymes in the dissolution medium and requires twotier dissolution testing. Studies have shown that drugs from cross-linked capsules are available in vivo to the patient, justifying the use of enzymes in the in vitro dissolution test. The literature contains several examples supporting evidence of cross-linking. However, confirming the degree of cross-linking continues to be a practical challenge due to a lack of quantitative procedures for measuring the extent of cross-linking and variability in options for formulations, excipients, level and types of stresses, and the experience level of the analysts. This article reviews the methodologies to confirm the evidence of cross-linking such as visual observation, capsule shell switch test, and spectroscopic determination of cross-linking, with an aim to facilitate the discussion and establishment of an acceptable standard approach.

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“…The degree of hydrolysis (DH) was determined by measuring the free amino groups by the trinitrobencensulphonic acid (TNBS) method [7] with modifications described by [8]. The determinations were done three times using an L-leucine standard curve and measuring the absorbance at 420 nm.…”

Section: Determination Of the Degree Of Hydrolysismentioning

confidence: 99%

Emulsifying Properties of Hydrolysates Isolated from Soybean Protein

Panizzolo

Añón²

2015

IJNFS

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Abstract:We have developed new surfactant agents based on hydrolyzed soybean proteins using papain, and we have studied their ability to form and stabilize emulsions. The interfacial behavior and the emulsifying properties were correlated to the structural changes that the proteins underwent. The hydrolysis reaction was stopped by dropping to pH 2 in one case, or rapidly dropping the temperature to -18ºC in the other. The structural and functional properties of the obtained products depended on the way the papain hydrolysis of the soy proteins was stopped. Hydrolysis did not have a beneficial effect on the emulsifying properties of those hydrolysates that were stopped by freezing. For all the degrees of hydrolysis we studied, the emulsifying properties of the isolates were significantly improved when the hydrolysis reaction was stopped by dropping to pH 2.

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The Quantification of Protein Amino Groups by the Trinitrobenzenesulfonic Acid Method: A Reexamination

Cited by 164 publications

References 77 publications

Co-polymer of histidine and lysine markedly enhances transfection efficiency of liposomes

Co-polymer of histidine and lysine markedly enhances transfection efficiency of liposomes

Dissolution of Gelatin Capsules: Evidence and Confirmation of Cross-Linking

Emulsifying Properties of Hydrolysates Isolated from Soybean Protein

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