Effect of high shear on proteins

Shear is present in almost all bioprocesses and high shear is associated with processes involving agitation and emulsification. The purpose of this study is to investigate the effect of high shear and high shear rate on proteins. Two concentric cylinder‐based shear systems were used. One was a closed concentric‐cylinder shear device (CCSD) and the other was a homogenizer with a rotor/stator assembly. Mathematical modeling of these systems allowed calculation of the shear rate and shear. The CCSD generated low shear rates (a few hundred s−1), whereas the homogenizer could generate very high shear rates (> 105 s−1). High shear could be achieved in both systems by increasing the processing time. Recombinant human growth hormone (rhGH) and recombinant human deoxyribonuclease (rhDNase) were used as the model proteins in this study. It was found that neither high shear nor high shear rate had a significant effect on protein aggregation. However, a lower melting temperature and enthalpy were detected for highly sheared rhGH by using scanning microcalorimetry, presumably due to some changes in protein's conformation. Also, SDS‐PAGE indicated the presence of low molecular‐weight fragments, suggesting that peptide bond breakage occurred due to high shear. rhDNase was relatively more stable than rhGH under high shear. No conformational changes and protein fragments were observed. © 1996 John Wiley & Sons, Inc.

[1]  Mike Hoare,et al.  Studies of the effect of shear on globular proteins: Extension to high shear fields and to pumps , 1981 .

[2]  P Dunnill,et al.  The effect of shear on globular proteins during ultrafiltration: Studies of alcohol dehydrogenase. , 1982, Biotechnology and bioengineering.

[3]  M S Croughan,et al.  Growth and death in overagitated microcarrier cell cultures , 1989, Biotechnology and bioengineering.

[4]  P Dunnill,et al.  Action of shear on enzymes: Studies with alcohol dehydrogenase , 1979, Biotechnology and bioengineering.

[5]  M S Croughan,et al.  Hydrodynamic effects on animal cells grown in microcarrier cultures , 1987, Biotechnology and bioengineering.

[6]  Y. Maa,et al.  Liquid-liquid emulsification by static mixers for use in microencapsulation. , 1996, Journal of microencapsulation.

[7]  J. Mitchell,et al.  The surface coagulation of proteins during shaking. , 1970, Journal of colloid and interface science.

[8]  T. Cartwright,et al.  The mechanism of the inactivation of human fibroblast interferon by mechanical stress. , 1977, The Journal of general virology.

[9]  E. Papoutsakis,et al.  Damage mechanisms of suspended animal cells in agitated bioreactors with and without bubble entrainment , 1990, Biotechnology and bioengineering.

[10]  D. Kirwan,et al.  Effects of stirring and sparging on cultured hybridoma cells , 1990, Biotechnology and bioengineering.

[11]  M Al-Rubeai,et al.  Estimation of disruption of animal cells by turbulent capillary flow , 1993, Biotechnology and bioengineering.

[12]  Chung C. Hsu,et al.  Liquid-liquid emulsification by rotor/stator homogenization , 1996 .

[13]  Y. Maa,et al.  Microencapsulation reactor scale-up by dimensional analysis. , 1996, Journal of microencapsulation.

[14]  E. Papoutsakis,et al.  Agitation induced cell injury in microcarrier cultures. Protective effect of viscosity is agitation intensity dependent: Experiments and modeling , 1992, Biotechnology and bioengineering.

[15]  M. Joniau,et al.  Stabilisation of Mouse and Human Interferons by Acid pH Against Inactivation Due to Shaking and Guanidine Hydrochloride , 1974, Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine.

[16]  P Dunnill,et al.  Action of shear on enzymes: Studies with catalase and urease , 1979, Biotechnology and bioengineering.

[17]  S. Charm,et al.  Shear effects on enzymes , 1981 .

[18]  R. Lewis,et al.  The effects of surface adsorption on the thermal stability of proteins , 1992, Biotechnology and bioengineering.