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Total protein quantification

Quantification of total protein content by amino acid analysis

Looking for fast protein quantification? We can quickly determine the quantities of 18 amino acids. These are the standard 20 amino acids except for tryptophan and cysteine.

Asparagine is determined as aspartic acid and glutamine as glutamic acid. The total protein amount is calculated from the sum of individual amino acid amounts.

Choose your service

Our PICK ‘n POST™ services are fast protein analysis without customization. You get quality results in easy to understand standard reports, at fixed prices.

Medium to high concentrations

Quantification of total protein content (AA analysis)

  • For proteins at medium to high concentrations
  • Hydrolysis of sample, quantification of 18 amino acids
  • Calculation of total protein content
$350.00
Per sample
Results in 4-8 days
Low concentrations

Quantification of total protein content – protein traces (AA analysis)

  • Proteins at low concentrations
  • Hydrolysis of sample, quantification of 18 amino acids
  • Calculation of total protein content
$450.00
Per sample
Results in 4-8 days
Service includes
  • Hydrolysis of your sample into free amino acids.
  • Ion exchange chromatography on amino acid analyzer.
  • Protein quantification of 18 amino acids with an accuracy of +/- 10%.
  • The total protein content is calculated from the summed amino acid amounts.
  • The analysis has sensitivity down to low microgram amount.
  • We deliver the report to you within 4-8 days.
Amino acids analysis

Amino acid analysis quantification results in table

Applications
Our customers typically use this analysis for the following applications:

Total protein content in complex samples

Traces analysis in food and consumer products

Sample requirements

Samples can be submitted in liquid form or as solid material.
Avoid very high salt concentrations.
Buffer that contain high amounts of primary amines, e.g. TRIS or glycine, may interfere with the ninhydrin reaction and provide false quantification data of specific amino acids.

Pipette 2-6 µg of liquid material into a 500 µl Eppendorf tube and lyophilize/speed vac it.
Alternatively provide 50-100 microliters (or more) of liquid material at minimum concentration of 0.1 microgram per microliter.
Solid material should be provided in sufficient amount for accurate weighing of samples at Alphalyse (mg material)

Technical details

This Amino acid analysis refers to the method used to quantify proteins and peptides.
Sixteen amino acids are quantified – the normal 20 amino acids except tryptophan and cysteine. Asparagine is determined as aspartic acid and glutamine as glutamic acid. The analysis process includes:

  • Protein hydrolysis
  • HPLC analysis
  • Data calculation
  • The Alphalyse procedure is based on the Ph. Eur and USP

The analysis is performed on a BioChrom 30 amino acid analyser by ion-exchange chromatography with post-column derivatization using ninhydrin. All amino acids except Proline (440 nm) are monitored at 570 nm.

 

Accuracy & Precision
For each batch run we include a duplicate analysis of a NIST BSA quality control standard. The results are used to determine the precision and the accuracy of the test. The precision should be below 5% and the accuracy within 15%.

Data calculations
A standard amino acid solution is analyzed for each 5 samples, and based on at least two runs, a compensation factor is calculated to correct for ninhydrin activity. Each amino acid in the sample is corrected by this compensation factor.
The total protein amount is calculated based on the amount of each amino acid (in pmol) multiplied by the mass of the given amino acid residue. Please note that as the content of cysteine and tryptophan is not included, the obtained value is underestimated by approximately 2.7% (average Cys and Trp content in proteins in the Swiss-Prot database).

Have questions? We'd love to help.

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