Chemical Testing of Proteins

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Chemical Testing of Proteins

Objective is to develop a chemical test that can test a sample to determine if the sample contains proteins

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Find research to support a method of testing that step

Biuret's Test is a simple chemical test that allows us to test for the presence of proteins

https://alevelbiology.co.uk/notes/test-for-proteins/#1-general-tests The test is extremely simple but the chemical's have some safety concerns but likely nothing not manageable. Updated Oct 19th 2023

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Test said Method

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Outline for other teams to integrate into the robot

Do Not Integrate until method is approved and tested

Mechanical: The system would need to be able to take a small sample 1-2ml and add the correct amounts of the other two liquids using pumps. There are safety concerns related to the tubing used for this system. The resulting test will then need to be waste disposed. Electrical: The pumps will need to be wired however the system will also need to be able to detect a purple ring appearing in the liquid likely using some form of camera or color sensor. This system could be sent through mission control as a picture to be viewed and approved but preferably wouldn't

Mission Control/Auton: Need to be able to decide if a test is successful test and send that information back to mission control so that the second test can then be performed.

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Biuret's Test

Intro: The Biuret test is used to test compounds having a peptide bond (protein).

Reagent Info: Biuret is a compound formed by heating urea to 180C

Chemical Process: Diluting copper sulfate (CuSO4) in alkaline condition reacts with compounds that contain two or more peptide bond to create a formation of co-ordination complex of cupric ions (Cu(+2)) with the unshared electron pairs of peptide nitrogen and O2 of water which turns the solution from blue to violet

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Ninhydrin test

Intro: The Ninhydrin test is used to test for amino acids

Reagent info: Ninhydrin is an organic compound that is stored in ethanol.

Chemical process: Ninhydrin is an oxidizing agent which reacts with the NH3 formed by amino groups to undergo oxidative deamination which produces ammonia (NH3), CO2, a corresponding aldehyde, and a reduced form of ninhydrin called hydrindantin. The ammonia then reacts with the ninhydrin and it's reduced product, hydrindantin, to produce diketohydrin (Ruhemanns Complex) which turns the solution from clear to blue.

Color changes:

• Development of a blue/purple color signifies the presence of ammonia, primary/secondary amines, and amino acids
• Development of a yellow color signifies the presence of hydroxyproline and proline
• Development of a brown color signifies the presence of asparagine
• No color change = no presence of any of the above mentioned

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Molisch's test

Intro: Molisch's test is a chemical test which is used to check for the presence of carbohydrates

Reagent info: Molisch's reagent is a mix of ∝- naphthol in ethanol

Chemical process: Molisch's test is based on the dehydration of sulfuric acid into furfural. When a sample containing carbohydrates is treated with sulfuric acid (H2SO4) and concentrated hydrochloric acid, water is used to eliminate the hydroxyl group from the sugar molecule to form furfural (C5H4O2). The furfural reacts with Molisch's reagent to produce a purplish-reddish ring between the point of contact of the H2SO4 and the analyte + Molisch reagent mixture which indicates the presence of carbohydrates