Top down vs bottom up proteomics

Two different strategies we can use to identify proteins with mass spectrometry.

[@96Regine]

I couldn't find a nicer video with this simplicity and great explanation for my students! And yes, Dr. Kelleher has done some great job, that guy is the Top Down beast!!! Thank you

[@sallycha7952]

The very best concise explanation! Thank you.

[@arnolddowney9807]

Honestly, great job! This was really well-done, both the explanations and the video and images to go with it. Just the right amount of humor too to shake it up. Off to check out the rest of your vids to help prepare for my final exam.

[@enavigator3821]

Thank you for the simplicity of your videos

[@lukassch8773]

Thank you for the Explanation :) Pure gold to find it in my Master's exam phase!

[@jikang7133]

I really love this one!!

[@TanTan-ch3vq]

You are the best, professor

[@ornithology11]

Godlike taste in music Sir.

[@profwatad]

really good explanation, thank you:)

[@sarahajian8102]

Thank you this was very useful

[@Automobilestats]

thankyou

[@seanfitzpatrick8385]

Is their a superior protein like whey, casein, plant? What is the difference between up regulated and down regulated protein?

[@TheTrailGlider]

Can you talk about Quantum SI's silicon chip they claim can do single-molecule protein sequencing? I am interested in this as an investor and have been watching your proteomics videos to try and learn more about this field.

[@shortchemistry7927]

Nice topic... as someone in the proteomics field, I'd love to see the day where high throughput, single molecule sequencing is routine. But protein sequencing is very different than gene sequencing. Proteomics will always be inherently more difficult, particularly when it comes to sample handling. Then again, as someone who has also founded a company in proteome sample preparation, perhaps my opinion is biased.

[@bgayatri11]

Hi Prof, in one part of the video you said that the z for the m/z needs to be identified. How is that done?

[@gokudegrees]

Hey, the recorded m/z = x = \frac{M + n\phi}{n}. for one peak to the left, y = \frac{M + (n+1)\phi}{n+1}. Thus, you can do some simplification and you can get that n, which is the number of charges, n = \frac{y-\phi}{x-y}

[@parthibanezhumalai2949]

Hi, How to determine molecular weight of the purified protein using tandem MS.

[@alandoucette9997]

If you measure the intact protein (top down), then the mass can be determined by determining the charge state through a deconvolution calculation. However, in a bottom up experiment, we are relying on other information. The assumption is that "somebody" has already studied this particular protein. They know the precise amino acid sequence, and therefore they know the mass. In bottom up, we identify just a piece of the protein by tandem MS. However, that piece maps onto the original (intact) protein. This information is available for millions of different proteins, in web databases.

[@Janopooh]

bottom... =)

[@Sebastian-dp9sk]

it is hard to pronounce PTM lol