To standardize a procedure for the determination of protein content by Warburg-Christian.
This procedure applies to all products that require the determination of protein by Warburg-Christian method.
Purified water – water from a deionizing system, resistivity > or = 18 MΩ•cm @ 25 °C
Analytical services laboratory personnel should follow this procedure as written.
Refer to Material Safety Data Sheets (MSDS) for hazards and appropriate handling precautions.
T = 25 °C, A260 nm and A280 nm, Light Path = 1 cm
Protein Sample Solution (Sample)
Prepare a solution containing approximately 0.3 mg protein/mL of sample in suitable buffer or purified water.
7.4 TEST METHOD
Measure the A260nm and the A280nm of sample in a suitable cuvette versus a suitable blank. The A280nm must be greater than the A260nm to obtain valid results. The presence of NAD or NADP will affect the A260nm and A280nm of proteins and thus, when necessary, must be corrected for in the calculations.
mg protein/mL = [(1.31 x A280) - (0.57 x A260)] x dilution factor
*correction for NAD or NADP
9. REFERENCES & ATTACHMENTS
Warburg, O. and Christian W. (1941) Biochem. Z. 310, 384-421