Name: 36.ヌクレオチド代謝 3 (36. Nucleotide Metabolism 3)
Uploaded: 2021-01-14T10:27:10.000Z
Duration: 50 min 57 s
Description: VoiceTubeの動画で発音を聞きながら英語表現を覚えよう！学べる英語：

基礎受動態

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JOANNE STUBBE: We're talking about the purine biosynthetic

I told you, in this part of it we were going to go through,

so at least you saw what the steps in the pathway are.

The key thing is you start out with the ribose 5-phosphate,

at a time, which is completely different from pyrimidines,

in this pathway that are universal in almost

And one of them we were going over-- two of them

but the role of glutamine in the purine and pyrimidine pathway

as the source of nitrogen. There were five of these enzymes.

Glutamine is one of the major ways you deliver ammonia

And purines and pyrimidines both have a lot of nitrogens.

and we had gone through the first few steps here,

was the second enzyme in the pathway, where we use ATP,

is the mammalian version of the pathway, which

but there were five different steps that require ATP.

see ATP use over and over and over and over again.

There are defined structures for the binding sites of the ATPs.

Once you have these in your brain, it becomes easy.

You might not know which one of these mechanisms it is,

but after you do a little bit of reading, or bioinformatics,

you can immediately tell what the structure of the enzymes

The other thing we talked about already was the role of folate.

Those are the three things I want you to get out of this,

and we're going to go through the rest of that today,

and then, after we finish that, we'll come back

because it speaks to the question of the importance

of transient protein-protein interactions in metabolism

inside the cell, which has been something that people have been

interested in for decades, and this paper in 2008

interesting to a lot of people, and we'll come back and talk

The first enzyme-- the names are horrible.

I gave you the names of all these things.

will have the purine pathway with the name stuck at the end.

I don't expect you to remember this, but we go from PRPP--

The reason I'm writing that again is because a key reason

that Bankovic's lab and my lab, many years ago,

was focused on this is because of the instability

This guy has a half life of 15 seconds at 37 degrees,

This is enzyme 1, and this is the first place

And I wanted to go back and say one more thing about that.

Again, there are two enzymes that use glutamine

This one is simply, if you look at the pathway displacing

pyrophosphate ammonia, you have a nucleophile displacing

pyrophosphate which, when complexed to magnesium,

The idea here is that all of these proteins,

and there were five of them, in the purine and pyrimidine

Sometimes the domains are separate polypeptides.

The glutaminase domain is in one of these domains,

the ammonia is going to displace whatever the leaving group is

in the second domain, requiring a tunnel that

varies from 25 to 40 angstroms to actually mediate

PurL is the fourth enzyme in the pathway.

It's upside down, and here's where the chemistry

that all of these enzymes in the active site have a cysteine.

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36.ヌクレオチド代謝 3 (36. Nucleotide Metabolism 3)

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