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What does LDL 5mM mean?

Rabdos

Well-Known Member
Messages
404
Type of diabetes
Type 2
Treatment type
Diet only
Hello!

LDL has 3,000 kDa molecular weight which means that 1mol of it weighs 3 tonnes.

When we say for a patient that LDL is 5mM we mean that they have 5mmol per 1L of their blood.

However, 5mmol of LDL would weigh 15kg!

What's wrong?
 
The molecular weight of LDL Cholesterol is 386.654 g/mol. 5 mmol/L is equivalent to 1933.25 mg/L or nearly 2 grams. I don't recognise the units kDa
 
Rabdos said:
kiloDaltons is a molecular mass unit. 1Dalton = 1g/mol by definition.
Here it says that LDL chylomicrons are 3million Daltons.
https://en.wikipedia.org/wiki/Low-density_lipoprotein

386g/mol is the molecular weight of cholesterol itself, not of LDL
Click to expand...
Could it be that when they give a figure of 5 mmol/L it means that is the density of the cholesterol from LDL particles rather than the density of the particles themselves.
 
Okay and what is the true LDL density then?
 
JohnEGreen said:
1 Da = 1 u = 1.660 539 066 60(50) ×10−27 kg,
Click to expand...

So one LDL molecule which is 3million daltons is 3 x 1.6 x 10-18 grams, so one mole is that times 6x10^23 equals 28x10^5 grams or 3tonnes, exactly what I said.
 
Rabdos said:
So one LDL molecule which is 3million daltons is 3 x 1.6 x 10-18 grams, so one mole is that times 6x10^23 equals 28x10^5 grams or 3tonnes, exactly what I said.
Click to expand...
Congratulations, although I am not sure that this information is of much practical use. Of course a LDL particle isn't actually a molecule.
 
@Rabdos Another general knowledge quiz or test.

And you are talking about units of mass and of course you not going to have a mole of LDL circulating in your system unless of course you circulatory system can accommodate a small VW car or the like and so like many of such threads this one in any practicable sense is totally irrelevant to diabetes.

A black hole can have the mass of several suns compressed into a singularity quite interesting but also totally irrelevant.
 
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