GRAS Screen™ 1 and GRAS Screen™ 2 were developed by Hampton Research for the crystallization of proteins, including monoclonal antibodies.
Each of the chemicals in GRAS Screen 1 and 2 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, and/or (5) a Everything Added to Food in the United States (EAFUS) substance.
Formulation is based on a) data mining databases such as the Protein Data Bank (PDB), BMCD, and in house Hampton Research data, b) review and analysis of the patent and scientific literature, c) input from academic and pharma colleagues, and d) in house testing.
The primary crystallization reagents in GRAS Screen 1 and 2 are Polyethylene glycol 300, 400, MME 550, 600, 1,000, MME 2,000, 3,350 and 4,000 (high concentration) versus 24 unique secondary salts (low concentration), sampling pH 4 to 9 without an added buffer. The screens can be considered an extension to the PEG/Ion screens, albeit with a focus on GRAS reagents.
GRAS Screen 1 samples four low molecular weight Polyethylene glycols (300, 400, MME 550, and 600) versus twenty-four salts, encompassing pH 4-9. GRAS Screen 1 is supplied in a 96 Deep Well block format and is compatible with robotic and multi-channel pipet liquid handling systems. GRAS Screen 1 is compatible with vapor diffusion, free interface diffusion, and microbatch crystallization methods. For research use only.
GRAS Screen 2 samples four medium molecular weight Polyethylene glycols (1,000, MME 2,000, 3,350, & 4,000) versus twenty-four salts, encompassing pH 4-9. GRAS Screen 2 is supplied in a 96 Deep Well block format and is compatible with robotic and multi-channel pipet liquid handling systems. GRAS Screen 2 is compatible with vapor diffusion, free interface diffusion, and microbatch crystallization methods. For research use only.
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