GRAS Additive


  • GRAS Additive™ is an optimization kit designed to evaluate 96 unique water soluble reagents and their ability to influence, promote and improve the crystallization of biological macromolecules.


  • Developed at Hampton Research
  • Bio focused additive screen for the optimization of biological macromolecular crystals
  • For use with soluble proteins, membrane proteins, and biological therapeutics
  • Generally Recognized As Safe reagent formulation
  • Compatible with vapor diffusion, microbatch, free interface diffusion


GRAS Additive is an optimization kit designed to allow rapid and convenient evaluation of 96 unique reagents and their ability to influence the crystallization of biological macromolecules, including but not limited to soluble proteins, membrane proteins, and biological therapeutics.1-5

The chemicals in GRAS Additive have been used under one or more of the following categories. As (1) a Generally Recognized As Safe (GRAS) substance, (2) a pharmaceutical excipient, (3) a normal physiological constituent, (4) a metabolic byproduct.5, and/or (5) a Everything Added to Food in the United States (EAFUS) substance.

The 96 by 1 ml, deep well block reagent screen, is designed to be compatible with most popular crystallization reagents including reagents utilized in Hampton Research screens. Compatible with vapor diffusion, microbatch, and free interface diffusion. For research use only.




GRAS Additive


1 ml, Deep Well block format



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Support Material(s)

Related Item(S)


1. Searching for silver bullets: An alternative strategy for crystallizing macromolecules. Alexander McPherson and Bob Cudney. Journal of Structural Biology 156 (2006) 387-406.

2. A novel strategy for the crystallization of proteins: X-ray diffraction validation. Steven B. Larson, John S. Day, Robert Cudney, and Alexander McPherson. Acta Cryst. (2007) D63, 310-318.

3. Development of an alternative approach to protein crystallization. McPherson, Alexander; Nguyen, Chieniang; Larson, Steven B; Day, John S; Cudney, Bob. J Struct Funct Genomics, Volume 8, Number 4, December 2007, 193-198.

4. Progress in the Development of an Alternative Approach to Macromolecular Crystallization. S. B. Larson,J. S. Day, C. Nguyen, R. Cudney, and A. McPherson. Crystal Growth & Design 2008 Volume 8, No. 8 3038-3052.

5. Wishart DS, Jewison T, Guo AC, Wilson M, Knox C, et al., HMDB 3.0 - The Human Metabolome Database in 2013. Nucleic Acids Res. 2013. Jan 1;41(D1):D801-7. 23161693.

6. Optimization of crystallization conditions for biological macromolecules. Alexander McPherson and Bob Cudney. Acta Crystallographica Section F Volume 70, Issue 11, pages 1445-1467, November 2014.

7. Screening and optimization strategies for macromolecular crystal growth. Cudney R, Patel S, Weisgraber K, Newhouse Y, McPherson A. Acta Crystallogr D Biol Crystallogr. 1994 Jul 1;50(Pt 4):414-23.