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Quantitation of Intact Proteins by Matrix Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF-MS)

Nathan G. Dodder and Michael J. Welch

Analytical Chemistry Division, Chemical Science and Technology Laboratory

National Institute of Standards and Technology, Gaithersburg, MD 20899-8392

One of the goals of proteomics is the quantitative measurement of protein concentrations in cells, tissues, and fluids. The level at which a certain protein is expressed, or at which it circulates in the blood, may be diagnostic of a corresponding disease state. Improvements in the measurement of a marker proteinís concentration will assist in the accurate diagnosis and treatment of the disease.

Matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) has the ability to ionize and measure proteins in an extract of human tissue or fluid. In our model system, human insulin served as the analyte and porcine insulin, which differed by one amino acid or 30 amu, served as the internal standard. Optimization and automation of the laser firing pattern reduced the effect of matrix crystal heterogeneity that can cause widely varying signal intensitities within a sample spot. The extraction from human serum, calibration curves, and quantitation of insulin will be presented.
 
 
 
 

Nathan G. Dodder and Michael J. Welch

Analytical Chemistry Division

Chemical Science and Technology Laboratory

Building 227, Room B154

Mail Stop 8392

Tel: 301-975-3389

Fax: 301-977-0685

E-mail: nathan.dodder@nist.gov

Not a Sigma Xi member.

Category: Chemistry