How are proteins used in lab?

[hitmankratos]

Hi,

I'm going to start my science-fair project for next year soon, and I have some questions in relation with proteins and experiments in lab...

 

1- Can a protein be extracted from something? What kind of material is used for that?

2- In lab tests, how can proteins be tested on cells? What kind of material again?

 

I am particularly interested in the protein TRAIL (TNF related apoptosis induced ligand) and their potential in destroying tumors when being carried by stem cells (http://www.medicinenet.com/script/main/art.asp?articlekey=100521).

Can anyone tell me about these sorts of proteins?

 

Thanks.

[CharonY]

1- They are generally either extracted from cells (and by extension, tissue), cell surface, cell compartments or directly from the media (in case of secreted proteins).

 

2- This is too general to be easily answered. It depends on what you want to test.

[hitmankratos]

Can you give me an example on something you've worked on or seen? Anything ! I just want to get an idea

[GDG]

As for extraction of proteins, two of the oldest examples are

1. curdling milk (extracting the casein) with an acid (vinegar, lemon juice, etc.)
   
2. extracting collagen from horse hides, hooves, etc. to make gelatin
   

[sockyee]

Proteins can also be produced en mass using bacteria and after that basically you can use HPLC to segregate out the protein for analysis. However, do take note that protein is very sensitive to denaturation and care must be taken to preserve it.

[CharonY]

One random example, overexpress an enzyme of a given metabolic pathway to alter cellular activity or try to direct metabolic fluxes. Or overexpress a regulator to affect gene transcription. Or use trypsin to segregate cell layers..or use antibody conjugates to visualize specific cellular elements or use toxicity tests (if the protein in question is a toxin, of course), and so on. Almost all cellular function are on way or another related to proteins, and obviously you can test about anything.

 

Sockyee, HPLC is basically only good for somewhat purified protein samples. Often just a affinity purification is done, sometimes an additional preparative HPLC can be done afterwards, depending on required purity.

But denaturation is usually not an issue anymore, as during the purification steps and most HPLC-systems they generally get denaturated anyway. Protein degradation is generally of greater concern.

Edited June 10, 2009 by CharonY

[GDG]

Hi,

I'm going to start my science-fair project for next year soon, and I have some questions in relation with proteins and experiments in lab...

 

1- Can a protein be extracted from something? What kind of material is used for that?

2- In lab tests, how can proteins be tested on cells? What kind of material again?

 

I am particularly interested in the protein TRAIL (TNF related apoptosis induced ligand) and their potential in destroying tumors when being carried by stem cells (http://www.medicinenet.com/script/main/art.asp?articlekey=100521).

Can anyone tell me about these sorts of proteins?

 

Thanks.

 

If TRAIL causes apoptosis, I would definitely wear gloves

 

You can buy TRAIL commercially, (for example at Axxora), but your budget may scream (US$360 for 20 ug).

 

If you are planning to isolate the protein yourself, I would suggest first tracking down the journal where it was first described. You can probably obtain the protein in the supernatant of a macrophage cell culture that has been stimulated in a particular way. The problems will be (a) making enough to detect, and (b) proving that you've made it at all. You can demonstrate that you've made it by using monoclonal antibodies, but again, they're not cheap.

 

Best of luck!