Gizmag: Injectable nanoparticles maintain normal blood-sugar levels for up to 10 days.

Fascinating technology featured in Gizmag & posted by someone HERE.

The nano-network that releases insulin in response to changes in blood sugar

"The injectable nano-network is made up of a mixture that contains nanoparticles with a solid core or insulin, modified dextran (which is commonly used to reduce blood viscosity), and glucose oxidase enzymes. When exposed to high levels of glucose, the enzymes convert glucose into gluconic acid, which breaks down the modified dextran to release the insulin. The gluconic acid and dextran, which are biocompatible, dissolve in the body, while the insulin brings the glucose levels under control.

The nanoparticles are given a positively or negatively charged biocompatible coating so that when they are mixed together, they are attracted to each other to form a “nano-network.” The positively charged coatings are made of chitosan, a material found in shrimp shells that has also found applications in self-healing car paint, while the negatively charged coatings are made of alginate, a material normally found in seaweed."

Wow! Cool bananas!

Enzymes

I have started to discuss my theory with Gary Taubes and this blog post is intended to go into a bit more detail about how stuff works. Trying to explain the following over the phone with hand-waving is likely to be very difficult, especially when I forget things!

Firstly, see Enzyme. Their name always ends in "ase". The thing about enzymes is that their activity can be increased & decreased by the level of substrate i.e. how much "stuff" there is going in to the reaction and how much "stuff" there is coming out of the reaction. Activation & inhibition can also be produced by other substances not directly involved in the reaction.

To get from Glucose (assuming muscle cells) to Pyruvate involves a multi-step process involving lots of different enzymes and other substances. Here's the first step.

Glucose + 1 molecule of ATP (Adenosine Tri-Phosphate) is converted by Glucokinase (with the aid of 2 Magnesium ions) into Glucose-6-phosphate + 1 molecule of ADP (Adenosine Di-Phosphate) + 1 Hydrogen ion. Here's the last step.

Phosphoenolpyruvate + 1 molecule of ADP is converted by Pyruvate kinase (with the aid of 2 Magnesium ions and 1 Potassium ion) into 1 molecule of Pyruvate + 1 molecule of ATP.

As stated in Everyone is Different , muscle cells at rest derive most of their energy from fat (Tri-Palmitin). Inside the cell mitochondria, molecules of Palmitoyl CoA (from Palmitate from hydrolysed Tri-Palmitin) produce energy starting with a process called beta-oxidation, where Acetyl CoA is repeatedly "snipped-off" yielding a fatty acid that's shorter by 2 carbon groups, 1 molecule of Acetyl CoA, 1 molecule of FADH2 + 1 molecule of NADH+H+ (don't ask!) until all that's left is Acetyl CoA. The molecules of Acetyl CoA enter the Krebs Cycle which produces more energy.

As muscle cells at rest derive most of their energy from Acetyl CoA rather than Pyruvate, Pyruvate accumulates. This inhibits the enzyme Pyruvate kinase causing an accumulation of Phosphoenolpyruvate. This inhibits the enzyme that produces Phosphoenolpyruvate etc etc. This results in an accumulation of Glucose-6-phosphate. This inhibits the enzyme Glucokinase causing an accumulation of Glucose. This inhibits the Glu-T4 transporters making muscle cells temporarily insulin resistant. Blood glucose stops entering muscle cells.

Things change when muscle cells undergoing anaerobic exercise use Pyruvate instead of Acetyl CoA. A lack of Pyruvate activates the enzyme Pyruvate kinase causing a lack of Phosphoenolpyruvate. This activates the enzyme that produces Phosphoenolpyruvate etc etc. This results in a lack of Glucose-6-phosphate. This activates the enzyme Glucokinase causing an lack of Glucose. This activates the Glu-T4 transporters making muscle cells temporarily insulin sensitive. Blood glucose enters muscle cells even if blood insulin level is normal.

The same principle applies to fat cells regarding glycerol-3-phosphate. In conclusion:
Within cells, the biochemical processes that produce "stuff" are not static but vary according to the needs of the cells.

I need a break!

While waiting to get hold of Taube's book Good Calories Bad Calories, I'm reading Toban Wiebe's Complete Notes to Good Calories, Bad Calories by Gary Taubes.

I'm also reading Anthony Colpo's latest articles on http://www.anthonycolpo.com/ . This guy doesn't mince his words!

How stuff works.

My last post got a bit technical and delved into the finer points of cell biochemistry. For those who would like to learn more about how cells work, I thoroughly recommend the book Metabolism at a Glance (Paperback) by Jack G Salway, Sen. Lecturer in Medical Biochemistry, University of Surrey. It's crammed with diagrams of metabolic pathways.

I've also got Medical Biochemistry at a Glance (Paperback) by Jack G Salway. EDIT: I thoroughly recommend this book, too.

For more general information on nutrition and metabolism, I recommend the book Introduction to Nutrition and Metabolism (Paperback) by David A Bender, Sen. Lecturer in Biochemistry, UCL.

A good website for medical biochemistry information is MedBio.info by Prof. em. Robert S. Horn.

A good website for enzyme structures is Enzyme Structures Database.

Here's a searchable version of Biochemistry by L Stryer. It's a bit dry, but of interest is Food Intake and Starvation Induce Metabolic Changes and Phosphatidate Is a Common Intermediate in the Synthesis of Phospholipids and Triacylglycerols.

Here's NCBI Bookshelf where you can search many textbooks.

Here's an absolutely humongous diagram in .pdf format of Metabolic Pathways. You need a fast machine to view this.

Update: Here are some cool Animations and Computer-Generated Movies by Harvard University.

Here's a YouTube video of ATP Synthase, which takes a proton gradient and, using a molecular motor-generator, converts ADP + Phosphate into ATP, the energy source that cells use.

Happy reading and viewing!