Overview of Strecker Amino Acid Synthesis
The Gibson Reaction (from Wikipedia) is a method used to synthesize all the essential amino acids from simple building blocks.
It involves the use of two chemicals called dithiocarbamates (DTC), which are the starting materials for the reaction. DTC are commonly found in nature and are often present in plants such as wheat bran or maize starch.
They have been isolated from bacteria, fungi, algae and other organisms.
These two chemicals can then react in a variety of different ways to form the various amino acids. The most common way to produce an amine group is with the use of an alcohol.
By adding the DTC and then an alcohol, the amine group can be directly added (as shown in the alanine synthesis below).
Overall, twenty different amines can be synthesized using this method.
Essential, or indispensable, amino acids cannot be synthesized by the human body and so must be supplied by food. Nine amino acids are considered essential and the remaining eleven are non-essential, meaning they can be synthesized from the essential ones.
The nine essential amino acids are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine.
These essential amino acids must be acquired from food because the body cannot produce them. In fact, the bodies of babies are unable to produce some of these amino acids and so they must get them from their mother.
The process of breaking down proteins, as well as synthesizing them, happens in the liver and the kidneys.
The first enzyme that takes part in the synthesis of these amino acids is the reductase. This enzyme is in charge of removing hydrogen from the various starting materials to produce aldehydes, which then react with the dicarbonyls or DTC to produce a formyl group.
Acyl carrier protein (ACP) is then used to bind the formyl group and carry the necessary parts to form a carbon-carbon bond.
There are four types of bonds that can be formed by the ACP, and these are known as Michael, Addition-E1cB, Addition-E2 and Levin.
After this, the amino group is added to the growing chain by being transferred from ammonium ion.
Finally, the remaining parts of the chain are all added until a complete protein has been formed.
Below is a short video of the entire process.
Now that you have an understanding of the process, let’s look at each of the twenty amino acids and when they were first synthesized.
The first amino acid to be produced during the process was Alanine. It was identified and isolated in 1878 by Austin.
He also discovered that it is one of the amino acids used in blood sugar metabolism.
The next amino acid to be produced was the simplest one, Histidine. It was the first one to be made synthetically in 1908 by Sumner.
This one was first made by combining HCl with the free base of Acetyl-methylcarbinol in 1917 by Pfanstiehl and Nettles.
In 1921, this one was isolated by combining formamide with ammonium thiocyanate.
The first person to produce this amino acid was George Campbell in 1879. He isolated it from casein, a protein found in milk.
This one was tried to be made in 1910 by the same people who made isoleucine. They used thioacetamide, but were not able to produce it.
This one was the very first amino acid to be made. It was done in 1866 by treating glycerine with potassium cyanate.
Threonine was the third amino acid to be made during this process. It was also made in 1917 by Pfanstiehl and Nettles.
This amino acid was first made in 1925 by Richard Clarke. He used d-glucose oxidase to cause the production of d-glucose and then converted it to d-xylamine.
This was then converted to d-tryptophan.
This one was first made by Fuchs in 1902 when he passed the vapors of Isoamyl alcohol over red hot carbon. This process caused isobutene to form and then under high pressure and steam it was converted into Valine.
Now we have all twenty amino acids that are used in the body to perform different tasks. If you would like to know the specific roles that each one plays, we have written an article that goes into detail for each one.
Here is the link: Roles of the 20 Amino Acids.
Now you know how amino acids are made for our bodies. It is important that we get them in our diet, or else we may suffer from many illnesses and the inability to produce proteins and enzymes.
Now you can impress your friends by telling them exactly how they are made!
Here is a printable version of this page.
Sources & references used in this article:
- Asymmetric catalysis of the Strecker amino acid synthesis by a cyclic dipeptide (MS Iyer, KM Gigstad, ND Namdev, M Lipton – Amino acids, 1996 – Springer)
- Assembly state of catalytic modules as chiral switches in asymmetric Strecker amino acid synthesis (N Kato, T Mita, M Kanai, B Therrien… – Journal of the …, 2006 – ACS Publications)
- Catalytic asymmetric Strecker synthesis. Preparation of enantiomerically pure α-amino acid derivatives from aldimines and tributyltin cyanide or achiral aldehydes … (H Ishitani, S Komiyama, Y Hasegawa… – Journal of the …, 2000 – ACS Publications)
- Catalytic enantioselective Strecker reactions and analogous syntheses (H Gröger – Chemical reviews, 2003 – ACS Publications)