Why Vitamin B is My Co-pilot

B vitamins play a major role in producing energy in the cells, but they certainly aren't top gun. They are converted in the body to act as coenzymes.

As coenzymes they have almost no independent catalytic power because they must rely on being temporarily bound as organic prosthetic groups to an apoenzyme, then called a holoenzyme (1p643).

In a very complex reaction of three enzymes and five coenzymes, four B vitamin-derivative coenzymes act in synergy with yet another coenzyme (lipoamide) to produce pyruvate dehydrogenase complex (1p750).

Thus, any deficiency of the four B vitamins—thiamine, riboflavin, niacin, and pantothenic acid—could severely impact cellular respiration.(1p750)

You could think of pyruvate dehydrogenase complex as a fighter jet equipped with B vitamin wingmen. The pilot is its substrate pyruvate, which later develops into that maverick of a central charcter in the citric acid cycle, acetyl CoA (1p751).

Reference

1. Denniston KJ, Topping JJ, Caret RL. General, Organic, And Biochemistry, 5th ed. New York: McGraw Hill; 2007.

Power-Saving Tips From Biochemistry

Need to lower the electric bill? You could learn a thing or two about conservation from your body's own cells.

Each one possesses a highly evolved system of energy efficiency that consists of regulatory enzymes (1). These catalysts can be activated and deactivated depending on conditions in the cell (1p649-651).

When strategically located as a first step or near-first step of a metabolic pathway, a regulatory enzyme acts as biochemical light switch.(2) The enzyme switches "on" and "off" effectively speeding up or slowing down pathway production and preventing any drain of effort.(2)

An example of three regulatory enzymes in action can be found in glycolysis, the 10-reaction pathway used to produce energy from carbohydrates(1p726):

1. Hexokinase catalyzes the first reaction of the pathway and is inhibited by high concentration of its own product.

2. Phosphofructokinase, the key regulatory enzyme, catalyzes the third reaction and is allosterically inhibited by glycolysis product, ATP, and intermediate, citric acid. This is an example of feedback inhibition.

3. Pyruvate kinase catalyzes the last reaction. Because it is activated by activation of phosphofructokinase through feedforward activation, it is allosterically inhibited by inhibition of phosphofructokinase.

In other words, the last enzyme in the pathway is saying, "First and third one out, don't forget to turn off the lights."

Reference

1. Denniston, KJ, Topping, JJ & Caret, RL. General, Organic, And Biochemistry, 5th ed. New York: McGraw Hill; 2007

2. Stavrianeas, S. Teaching glycolysis regulation to undergraduates using an electrical power generation analogy. Adv Physiol Educ. 2005;29:128-130. Available at: http://advan.physiology.org/cgi/content/full/29/2/128-a. Accessed on Nov. 15, 2008.

Deeply Flawed

Our bodies are not perfect. Far from it. In fact, they have serious flaws. Most importantly, its greatest flaw is that one day it will die. Over time evolution decided it preferred that humans die so those younger, stronger kids can take over eating, mating, etc.

You and I may not be OK with dying. If we pour effort or money into anything, it should be in trying to keep ourselves living longer. Live long and forever, if at all possible. Gosh, I think I'll have to dedicate my life to learning about longevity.

Most of all, longevity of the brain. The way I se it, if my brain goes, I pretty much am done too. Gotta study longevity, brain health, etc.

Choline for adrenaline

Ciara is driving home from school, listening to her favorite music, when a dog darts into the street in front of her car. She manages to swerve to avoid hitting the dog. As she continues on her way she notices her heart is racing, she has "goose-bumps" and her hands are sweaty.

When the dog darted in front of Clara's car, her body went through a sympathetic "fight-or-flight" response, which is an inborn, automatic effect that can occur under conditions of acute stress.(1&2) The effects may have also included pupils dilating, airways to her lungs dilating, blood vessels to her kidneys and gastrointestinal tract constricting, blood vessels involved in exercise to fight off danger dilating, release of glucose by the liver, liver cells performing glycogenolysis.(1p537)

The effect is triggered by acetylcholine released from sympathetic nerves, which can activate many tissues simultaneously.(1p537 & 2) A release of adrenaline and norepinephrin from the medulla of the adrenals facilitate the intense physical effects.(2) We share this response with many other animals.(2)

Gives you a new reason to make sure you get the choline you need daily for synthesis of acetylcholine.

References

1. Tortora, GJ & Derrickson, B. Principles of Anatomy and Physiology, 11th ed; 2006. New York: John Wiley & Sons.
2. Psychologist World. Stress: The fight or flight response. Available at: http://www.psychologistworld.com/stress/ fightflight.php. Accessed on Oct. 25, 2008.

I am 99% bacteria, 1% human

Sounds really creepy, but it's true. And we count on all our little friends to keep us healthy, keeping our gastrointestinal tract functioning and absorbing minerals well, and producing the critical vitamin K that is so important to our lives. Vitamin K, made by the large intestine flora, is vital for synthesis of clotting factors that make up normal blood clotting. It also helps inhibit osteoporosis by keeping calcium out of your arteries and in your bones.

So next time you need to get rid of an infection and are on antibiotics, be sure to repopulate and grow your gut flora with probiotics and prebiotics to keep yourself healthy long-term.

A Tale of Two Bacterial Strains

It was the hottest of times, it was the coldest of times, and it was billions of years before the French revolution when one bacterial strain became two and possibly a few more.1p630 One of these strains would thrive in what we now know to be the Arctic Cold.1p627 Another would survive in the vents of a volcano.1p627 Not so coincidentally, both strains depend on vital functions of hexokinase.1p627 Normally hexokinase would become denatured while exposed to hot, molten rock.1p627

How does the volcano strain survive? The answer lies in significantly more R group interactions of amino acids found in holding its tertiary structure together.1p630 These noncovalent interactions play their role of stability via hydrogen bonding, ionic bonding and van der Waals forces.1p614 The extra support keeps hexokinase's globular protein alpha-helix and beta-pleated sheets from unfolding.1p609

Although perhaps not nearly complex as R group interactions, the bacterial strains would require another variation: maintaining membrane fluidity.1p582 The two bacterial strain's membrane lipids differ in their ratios of saturated and unsatured fats.1p582 While North Pole bacteria require a greater percentage of unsaturated fat double-bond "kinks" for their membranes to stay fluid, the membranes of bacteria in a firy environment are usually made up of a higher percentage of saturated fats.1p582

What does this information mean for humankind? The mystery of the beginning of life may partially lie in how both bacterial strains developed. Animals and plants both contain hexokinase, which plays roles in glycolysis and possibly sugar signal transduction pathways.1p726 & 2 Additionally all cells contain membrane lipids.1p557 Thus, the more we learn about these bacteria, the more we may learn about ourselves and our own humble origins.

References

1. Denniston, KJ, Topping, JJ, Caret, RL. General, Organic, and Biochemistry, 5th ed. New York: McGraw Hill; 2007.

2. Sheen, J, Jang, J. The role of hexokinase in plant sugar signal transduction and growth and development. Plant Molec Biol. 2000;44:451–461. Available at: http://genetics.mgh.harvard.edu/sheenweb/reprints/sugarPMB00.pdf. Accessed on November 5, 2008.

Lecithin - good for your brain and liver

Lecithin provides choline, which is a precursor for the neurotransmitter acetylcholine in the brain.(1) Choline is also necessary to remove fat from the liver.(2) Thus, supplementation could be extremely beneficial for alcoholics to prevent against cirrhosis.(2)

References

1. http://www.jacn.org/cgi/content/abstract/11/5/473
2. http://www.medschool.northwestern.edu/newsworthy/past-years/2002/2002H-May/choline.htm