Advanced Nutrient Metabolism: Pyruvate--Acetyl CoA and Pyruvate-- Lactate, Lactate Metabolism and PPP

I mentioned before , fructose ( which is excited by glucokinase in the liver) gets phosphorylated in the cell into fuctose 1-P ( using up one ATP) which then gets converted to glyceraldehyde 3-P. This glyceraldehyde is the backbones of triglycerides ( glycerol with three attached fatty acids). High fructose syrups/ high fructose intake is thought to impact this process by 1. Exciting glucokinase , stimulating the glycolysis of glucose--> pyruvate-->acetyl CoA.

Acetyl CoA is the building blocks of..... Lipids! More fat!
and 2. Fructose turning into glyceraldehydes ups your triglyceride levels- which can increase your insulin resistence - which increases insulin release- which increases blood glucose-- which means Diabetes to follow!




PPP is the pentose phosphate pathway.

We use this pathway to bar off glucose for a little while. Why you may ask? Of course, to make it into other important stuff -
1. ribose- so we can form nucleic acids , DNA... and
2. So we can make NADPH2.

NADPH2 is involved in this cute little process that lets us get rid of a free radical.. h2 O2 ..hydrgoen peroxide. If we do not get rid of it, it will cause our red blood cells to burst- Not GOOD !!

So, NADPH2 interacts with Glutathione ( 2 GSH)... which requires an enzyme ( of course!) Glutathione Peroxidase - this turns H2O2 ( the bad guy) into H2O.. water!

The PP Pathway starts with 3 molecules of glucose

glucose-6-P glucose 6-P glucose 6-P

--with the help of glucose-6-p-dehydrogenase----key enzyme (again with the enzymes)

-6phosphogluconate -6phosphogluconate-6 phosphogluconate


these each break-off Carbons as CO2 ... and Turns NADP into NADPH2 ( horrary!)
making

5-Carbon Compound - Ribose ( yah!) - 5 carbon Compound

These all can easily convert to...

glucose -6- P -glucose-6-P and -glyceraldehyde

All of which can go back to glycolysis or the g-6-p's can go to glycogenesis


Lactate Metabolism!

I know you all are dying to know this!

So glucose---> pyruvate ---> Acetyl CoA ( in high oxygen situations)
Well in low oxygen situations, or say high demand exercise
pyruvate---> lactate
this conversion also gives us the ultra-important taxi: NAD+

NAD+ is a taxi that goes back to the glucose stage to convert glucose--> pyruvate (aka glycolysis)

This is important in keeping us alive- without oxygen, lactate gets sent into the blood, then into the liver, then gets conerted there back to pyruvate and back to glucose- then back to the beginning of glucose.


I am done! I took my test and feel VERY good about it- keep your fingers crossed!
Thanks for reading about Nutrient Metabolism!

Advanced Nutrient Metabolism: Glycogenesis-- Glycogenolysis---Glycolysis----

Glycogenesis
The formation of glycogen. After you eat, your body will store glycogen in muscle tissue and in liver cells. Your liver & muscle will use this for when you place a demand on your body such as exercise. Your liver also regulates/maintains blood glucose levels as needed so glycogen storage is also important for liver functioning.

It only uses 1 ATP (energy molecule) to branch 1 glucose onto/to form glycogen..BUT its such a good deal because when we break apart glycogen we ultimately get 36-38 ATP's worth of energy! Talk about bang for your buck!

The liver also acts as a vacuum ( :-(.. i wish I could afford a i-Roomba!)... it collects all this other "crap" laying around ( i.e lactate) to form glycogen. This is called gluconeogenesis and a significant amount of glycogen formation depends on this process ( about 1/3).

Pathway:
Glucose ( from our food) interacts with either these two enzymes
--- hexokinase in the muscle cells and liver
---glucokinase in the liver only

Then glucokinase stimulates glucose to use up 1 ATP and forms glucose-6-phosphate
Glucose-6-phosphate----> glucose 1-phosphate
glucose-1-phosphate----helped by Uridine Triphophate UTP---> UDP-glucose
UDP glucose----helped by glycogenin primer---> Unbranched Glycogen
Unbranched glycogen--- helped by Glycogen Synthase ( branching enzyme)--> Branched, Glycogen

Hooray! So Now that we have stored glucose into a better branched form- What happens when we need the energy?

Glycogenolysis!

Liver glycogen gets exported to blood
Muscle Glycogen gets exported to muscle cells

This is stimulated/turned on ( ooh la la) by glucagon and epinephrine ( thus these are called allosteric modifiers because they influence the enymes- glycogen synthase ( forming glycogen) AND glycogen phosphorylase

Glycogen phosphorylase is a big enzyme in glycogenolysis and is also turned on/off + / - (modified) by cyclic AMP

Pathway

Fasting/Starving + -> glucagon in liver + with the help of Protein Complex + Adenylate Cyclase

Flight or fight Ahh!!! + epinephrine + with the help of Protein Complex + Adenylate Cyclase

+ Adenylate Cyclase ---- +

is all excited, uses up a molecule of energy ATP...... > forming Cyclic AMP (cAMP)

cAMP is interacts with protein kinases that inhibit the branching enzyme glycogen synthase I mentioned above by turning it into the inactive form (B)
cAMP is thus modified by Protein dependent kinases... first the inactive forms then turn to active... which then turns phosphorylase kinase B inactive to active...

Phosphorylase A --- > breaks down Glycogen---> Glucose-1-phosphate ---> glucose ! and lactate


So now we have lots of free glucose to use up
Glycolysis!
glucose---> pyruvate
yeilds total of 2 ATP but in the future we will know that we end up with more b/c of krebs cycle

Red Blood Cells depend on glycolysis because they have no mitochondria, as do Eye cells as well as they have limited blood supply.
Our Kidneys, Testis, leukocytes and White Muscle Fibers all have no mitochondria so we need this process as well.

If we have high levels of ATP , high levels of alanine, hexokinase and Citrate- these all inhibit glycolysis

High levels of fructose "turn on" glucokinase which turns on glycolysis
The main control point is PFK .. phophofructokinase which can turn on or off the production of fructose and hence the glycolysis process.

Pathway (this is a doozy)

Glucose--- gets into the cell as glucose and is phosphorylated using up 1 ATP to make-->
Glucose-6-Phosphate---isomerase turns this into---> Fructose -6-Phosphate
Fructose -6-Phosphate---uses another ATP---> Fructose 1-6-Phosphate

Fructose 1-6-P is then broken down into Glyceraldehyde 3-P and dihydroxyacetone-3-P (DHAP)

DHAP--- runs into NADH-- froms NADH2 ( which will give us 3 ATP x 2 for krebbs later) and then can turn into Glyceraldehyde 3-P like the other molecule formed

Glyceraldehyde-3-P makes a 3 Carbon Intermediate #1 (3CI #1)

3C I #1 MAKES 1 ATP (x 2 because 1 glucose moledule yeilds 2 carbons so this process is doubled) --- forming 3 C I #2 --- which changes to 3C I #3

3cI#3 turns into PEP ( phosphoenolpyruvate)

PEP MAKES 1 ATP (x 2) by changing into Pyruvate !

Pyruvate is then turned into Acetyl CoA ( high oxygen conditions, which also forms NADH2 ( future yeild of 6 ATP) or Pyruvate forms Lactate ( no oxygen, which takes NADH2 and forms NAD + which then acts as a taxi to keep the cycle going).

The pyruvate---> lactate is the process that keeps us alive say when we are drowning and have no Oxygen- ( it only lasts for about 400 kcal worth of energy) .. The taxi NAD+ goes back up to help convert glucose to pyruvate so we can continue to have energy!

And I didn't even look at my notes for any of this!! Phew!!!

HFCS

I spent SO much time shopping with KC this morning/afternoon that I got home and was really hungry for lunch. I heated up leftover pasta and sauce for Jeff and I before yardwork.

I started to pack for the beach, showered, laundry, then got ready and left for class- before I left I grabbed a balance bar and ate it on the way to class.

Manicure After Class!!

Note to self- iatria day spa did not do a very good job but it was later at night and the last appointment of the day so not sure if we should try this place again.... Dinner Finally!!!





Dinner:
Starving!! I had a salmon burger and toasted in the toaster oven. I had a whole wheat mini wrap with hummus and goat cheese and goddess dressing. I also had a big bowl of mixed veggies that was delicious!

Body: Rest day- sort of- I walked - a lot! and all the unpacking/laundry/run around/cleaning worked up a sweat! But no formal exercise today! See how heavy my mind section is!

Mind: Class was interesting! Adv. Nutrient Metabolism is always fun.
Today was glycolysis...

I will spill about high fructose metabolism ( only a tiny portion of what we went over) because it is such a buzz recently.

( you can refer back to my posts late september to refresh on saccharides)

Glucose, Galactose, Fructose all require ATP (adensosine tri-phosphate= energy!) to be broken down.

Glucose gets phosphorylated (using a phosphate from ATP) into Glucose 1-P, which uses either hexokinase or glucokinase ( gluco in the liver, hexo outside liver) to convert to Glucose-6-P.... which gets converted to Fructose-6-P ..

Fructose needs ATP to get phosphorylated as well and gets converted to Fructose 6- P via enzymes ( phosphofructokinase- PFK- the main regulator in the breakdown process) ...

From here...
Fructose 6-P breaks down to glyceraldehydes ( 2 of them since its a 3 carbon molecule and glucose is a 6 carbon molecule)..

Glyceraldehydes get further broken down into carbon intermediate chains, then into pyruvate (with the help of high ATP, High alanine levels, and the pyruvate kinase enzymes). Pyruvate is the end result of glycolysis along with 2 ATP

( pyruvate can then continue to break down in mitochondria- if no oxygen is present it will convert to lactic acid.... if oxygen is present it will convert to Acetyle CoA which is the building block for fat AND cholesterol)


Unfortunately, science has shown that high fructose intakes result in high amounts of glyceraldehydes. The problem with this is that triglycerides ( glyercol with three fatty acid chains attached) are made from this via the available glycerol in glyceraldehydes.

Thus ....high fructose intake results in higher fat production. If you regularly consume a healthy diet and exercise regularly- consuming a single product or maybe a few products with HFCS isn't really going to do anything that harmful except for potentially create a few extra triglycerides ( unless you exercise or output energy which will immediately breakdown everything to pyruvate b/c of energy demand). If your triglyceride levels are already high, you would want to stay away from HFCS. In general, you want to stay away from HCFS because the majority of products that contain it aren't healthy products anyway- pre-packages snacks/cakes/cookies etc. arent nutritious foods.


Hope you enjoyed that! It helped me recap my class too!

Soul:
Manicure! Shoe Shopping! ( I got fabulous shoes!!!!!), Makeup shopping, Laundry, Talked to my mom about my day and my knee issues, Greys Anatomy, Going to THE BEACH!!!! WOOOOOOHOOOOOOOOOOO!!!!



wait, did i already say... WOOOOHOOOOOOOO!!

bringing the laptop and the camera stuff but not sure if our house has wireless!
see you later tomorrow!