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/sci/ - Science & Math

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8092775 No.8092775 [Reply] [Original]

not trolling and its not hw or anything, im just doing a lab report, but i have a dumb question

if my calculated protein concentration in 1 mL of extract from a food sample is 11.2 mg/mL

how do i calculate the protein as a percentage of a 5g sample of the same food item? like what info do i need?

heres what i did:

took 5 g of soybeans, ground them to uniform powder, dried them in a moisture balance, defatted them with hexane extraction, then solubilized proteins with water and NaOH, added acid and ppt to isoelectric pt, centrifuge, collect protein, solubilize again, and take 1 mL of this solution, dilute to 5mL and do Biuret method, obtain absorbance, obtain concentration using standard curve (previously developed)

how do i go back to determining protein content as a percentage of the entire sample? im literally drawing a blank right now

>> No.8094005

you say you obtained absorbance, from that you can calculate concentration:

A = extinction coefficient x concentration x length cuvette

then

c = n/v ; m = n x M

now, for example if you had 30 µL sample and in that sample you have 37,5 µg protein which is equal to a concentration of 1,25 mg/mL

total amount of protein in, for example 3 mL sample (in a cuvette) is 1,25 mg/mL x 3 mL = 3,75 mg

hope this helps

>> No.8094085

What the fuck? Are those 'shutterstock' pictures a troll? Everytime there is somebody using a wrench completely out of context. Just look at that fucking pic, she is using a wrench to fucks know what to do on a simplistic model of a DNA strand
Sorry to not even address your question OP.

>> No.8094089

>>8092775
>Wearing science glasses when working on your dna atoms.

>> No.8094946
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8094946

>its not hw
>im just doing a lab report

>> No.8094957

>>8092775
you need to know the mass of the original food sample you extracted the protein from. then you have a concentration by mass (mg protein per gram food item). Then you just multiply that coefficient by 5g

>> No.8095659

>>8094005
Yea man, i have the concentration per mL already
>>8094085
>>8094946
kek
>>8094957
So i extracted the protein from 5 g of defatted soybean meal. However, i didnt quantify total mass of tge protein. I just dissolved the sample etc etc and got 1 mL for Biuret test

Theres no way i can get that info now is there