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Ariki R.,University of Tsukuba | Hirano A.,University of Tsukuba | Arakawa T.,Alliance Protein Laboratories | Shiraki K.,University of Tsukuba
Journal of Biochemistry | Year: 2011

We have recently proposed the application of solubilizing effects of arginine to poorly soluble aromatic compounds for drug discovery research. In this study, we compared the solubilizing effects of arginine with those of other amino acids, salts and a surfactant using alkyl gallates as model drug substances of low aqueous solubility. The solubilizing effects of arginine on the alkyl gallates were distinct compared with those of other amino acids and salts; the effects were even greater than those achieved using a strongly chaotropic guanidinium ion. Transfer free energy of the alkyl gallates from water to arginine solution depended weakly on their dissolution free energy in water, which is in contrast to sodium dodecyl sulphate that showed strong dependence. The present results suggest that arginine solubilizes alkyl gallates through interaction with the aromatic moiety and sodium dodecyl sulphate does so by interacting with alkyl groups. © 2011 The Authors.


Hirano A.,Japan National Institute of Advanced Industrial Science and Technology | Arakawa T.,Alliance Protein Laboratories | Kameda T.,Japan National Institute of Advanced Industrial Science and Technology
Journal of Chromatography A | Year: 2014

This study highlights the ability of arginine to elute bovine serum albumin (BSA) and a monoclonal antibody against interleukin-8 (mAb-IL8) from Capto MMC, which is a multimodal cation exchanger. Arginine provides high recovery of monomeric BSA from Capto MMC chromatography columns at yields similar to NaCl elution, and oligomeric BSA was more readily eluted by arginine than by NaCl. The effectiveness of arginine as an eluent also enabled the separation of monomeric BSA from the oligomeric forms. The purification of mAb-IL8 was successfully achieved using Capto MMC chromatography and arginine as the eluent. The mechanism of the effects of arginine on protein elution was determined by calculating the binding free energy between arginine and Capto MMC using molecular dynamics simulations. The overall affinity of arginine for Capto MMC was associated with electrostatic interactions. However, additional affinities contributed by hydrophobic interaction or hydrogen bonding were also observed to play a role in the interaction between arginine and Capto MMC, which likely results in the characteristic elution by arginine. © 2014 Elsevier B.V.


Shikiya Y.,University of Tsukuba | Tomita S.,University of Tokyo | Arakawa T.,Alliance Protein Laboratories | Shiraki K.,University of Tsukuba
PLoS ONE | Year: 2013

Nonspecific adsorption of protein on solid surfaces causes a reduction of concentration as well as enzyme inactivation during purification and storage. However, there are no versatile inhibitors of the adsorption between proteins and solid surfaces at low concentrations. Therefore, we examined additives for the prevention of protein adsorption on polystyrene particles (PS particles) as a commonly-used material for vessels such as disposable test tubes and microtubes. A protein solution was mixed with PS particles, and then adsorption of protein was monitored by the concentration and activity of protein in the supernatant after centrifugation. Five different proteins bound to PS particles through electrostatic, hydrophobic, and aromatic interactions, causing a decrease in protein concentration and loss of enzyme activity in the supernatant. Among the additives, including arginine hydrochloride (Arg), lysine hydrochloride, guanidine hydrochloride, NaCl, glycine, and glucose, Arg was most effective in preventing the binding of proteins to PS particles as well as activity loss. Moreover, even after the mixing of protein and PS particles, the addition of Arg caused desorption of the bound protein from PS particles. This study demonstrated a new function of Arg, which expands the potential for application of Arg to proteins. © 2013 Shikiya et al.


Tsumoto K.,University of Tokyo | Arakawa T.,Alliance Protein Laboratories | Chen L.,Life Technologies
Current Pharmaceutical Biotechnology | Year: 2010

Protein refolding is still on trial-and-error basis. Here we describe step-wise dialysis refolding, in which denaturant concentration is altered in step-wise fashion. This technology controls the folding pathway by adjusting the concentrations of the denaturant and other solvent additives to induce sequential folding or disulfide formation. © 2010 Bentham Science Publishers Ltd.


Inoue N.,University of Tsukuba | Takai E.,University of Tsukuba | Arakawa T.,Alliance Protein Laboratories | Shiraki K.,University of Tsukuba
Molecular Pharmaceutics | Year: 2014

Unacceptably high viscosity is observed in high protein concentration formulations due to extremely large therapeutic dose of antibodies and volume restriction of subcutaneous route of administration. Here, we show that a protein aggregation suppressor, arginine hydrochloride (ArgHCl), specifically decreases viscosity of antibody formulations. The viscosities of bovine gamma globulin (BGG) solution at 250 mg/mL and human gamma globulin (HGG) solution at 292 mg/mL at a physiological pH were too high for subcutaneous injections, but decreased to an acceptable level (below 50 cP) in the presence of 1,000 mM ArgHCl. ArgHCl also decreased the viscosity of BGG solution at acidic and alkaline pHs. Interestingly, ArgHCl decreased the viscosity of antibody solutions (BGG, HGG, and human immunoglobulin G) but not globular protein solutions (α-amylase and α-chymotrypsin). These results indicate not only high potency of ArgHCl as an excipient to decrease the solution viscosity of high concentration antibodies formulations but also specific interactions between ArgHCl and antibodies. © 2014 American Chemical Society.


Arakawa T.,Alliance Protein Laboratories | Tsumoto K.,Tokyo Medical University | Ejima D.,Ajinomoto Co.
Biochimica et Biophysica Acta - Proteins and Proteomics | Year: 2014

Protein-A or Protein-L affinity chromatography and virus inactivation are key processes for the manufacturing of therapeutic antibodies and antibody fragments. These two processes often involve exposure of therapeutic proteins to denaturing low pH conditions. Antibodies have been shown to undergo conformational changes at low pH, which can lead to irreversible damages on the final product. Here, we review alternative downstream approaches that can reduce the degree of low pH exposure and consequently damaged product. We and others have been developing technologies that minimize or eliminate such low pH processes. We here cover facilitated elution of antibodies using arginine in Protein-A and Protein-G affinity chromatography, a more positively charged amidated Protein-A, two Protein-A mimetics (MEP and Mabsorbent), mixed-mode and steric exclusion chromatography, and finally enhanced virus inactivation by solvents containing arginine. This article is part of a Special Issue entitled: Recent advances in molecular engineering of antibody. © 2014 Elsevier B.V.


Brown and coworkers (Eur. Biophys. J. 38 (2009) 1079-1099) introduced partial boundary modeling (PBM) to simplify sedimentation velocity data analysis by excluding species outside the range of interest (e.g., aggregates, impurities) via restricting the sedimentation coefficient range being fitted. They strongly criticized the alternate approach of fitting g(s z.ast;) distributions using similar range limits, arguing that (i) it produces "nonoptimal fits in the original data space" and (ii) the g(s z.ast;) data transformations lead to gross underestimates of the parameter confidence intervals. It is shown here that neither of those criticisms is valid. These two approaches are not truly fitting the same data or in equivalent ways; thus, they should not actually give the same best-fit parameters. The confidence limits for g(s z.ast;) fits derived using F statistics, bootstrap, or a new Monte Carlo algorithm are in good agreement and show no evidence for significant statistical distortion. Here 15 g(s z.ast;) measurements on monoclonal antibody samples gave monomer mass estimates with experimental standard deviations of less than 1%, close to the confidence limit estimates. Tests on both real and simulated data help to clarify the strengths and drawbacks of both approaches. New algorithms for computing g(s z.ast;) and a scan-differencing approach for PBM are introduced. © 2011 Elsevier Inc. All rights reserved.


Arakawa T.,Alliance Protein Laboratories | Kita Y.,Keio University
Current Protein and Peptide Science | Year: 2014

Arginine is widely used in such applications as protein refolding, solubilization of proteins and small molecules, protein and small molecule formulation, column chromatography and viral inactivation as summarized in this review. What makes arginine effective in these applications is largely based on its ability to suppress protein-protein interactions and protein-surface interactions. The mechanism of these widespread effects of arginine on proteins can be explained at least in part from its unique interactions with the protein surface. Here we describe the modes of the interactions of arginine with model compounds and proteins and also water molecules, and then attempt to explain the mechanism of its effect on proteins by comparing with the interactions that occur between protein and protein denaturants or stabilizers. © 2014 Bentham Science Publishers.


Yoshikawa H.,University of Tsukuba | Hirano A.,University of Tsukuba | Arakawa T.,Alliance Protein Laboratories | Shiraki K.,University of Tsukuba
International Journal of Biological Macromolecules | Year: 2012

Ethanol is used to precipitate proteins during various processes, including purification and crystallization. To elucidate the mechanism of protein precipitation by alcohol, we have investigated the solubility and structural changes of protein over a wide range of alcohol concentrations. Conformation of hen egg-white lysozyme was changed from native to α-helical rich structure in the presence of ethanol at concentrations above 60%. The solubility of lysozyme was reduced with increasing ethanol concentration, although gel formation at ethanol concentrations between 60% and 75% prevented accurate solubility measurements. SH-modified lysozyme showed largely unfolded structure in water and α-helical structure in the presence of ethanol. More importantly, solubility of the chemically modified lysozyme molecules decreased with increasing ethanol concentration. There is no indication of increased solubility upon unfolding of the lysozyme molecules by ethanol, indicating that any favorable interaction of ethanol with the hydrophobic side chains, if indeed occuring, is offset by the unfavorable interaction of ethanol with the hydrophilic side chains and peptide bonds. © 2011 Elsevier B.V.


Hirano A.,University of Tsukuba | Kameda T.,Tokyo Science and Industrial Research Institute | Arakawa T.,Alliance Protein Laboratories | Shiraki K.,University of Tsukuba
Journal of Physical Chemistry B | Year: 2010

The poor aqueous solubility of drug substances hampers their broader applications. This paper describes a de novo strategy to increase the aqueous solubility of drug substances using an arginine-assisted solubilization system (AASS) with alkyl gallates as model drug substances. Solubility experiments of alkyl gallates showed that arginine greatly increases the aqueous solubility of different alkyl gallates, whose aqueous solubilities differ widely. In contrast, lysine showed marginal effects on alkyl gallates solubility. Molecular dynamic simulation indicated a greater interaction of arginine with alkyl gallates than that of lysine, which reflects favorable interaction between the guanidinium group of arginine and the aromatic ring of alkyl gallates. Such interaction apparently disrupts association of alkyl gallate molecules, leading to solubilization. These results indicate AASS as a promising approach to solubilize poorly soluble drug substances containing aromatic ring structures. © 2010 American Chemical Society.

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