What is a peptide?

My friend Deb asked for a short explanation of peptides (“50 words or less”, she said), but if you know me, you know that I can’t give a short explanation of anything! I’m going to cut and paste a few things about peptides that I’ve written or that I’ve found on the web so that you have a clearer understanding of what a peptide is.
The first piece is cut and pasted from wisegeek.com and gives a scientific, yet easy to understand explanation of peptides, but doesn’t necessarily tell you how it relates to skin care. It’s a good place to start, though.

Wisegeek.com says:
Peptides are compounds which are formed by linking one or more amino acids with a covalent bond. These compounds are classified as polymers, because they typically link together in long chains. All animals on Earth have peptides in their body, and in a way, peptides are one of the building blocks of life. When a peptide chain gets especially long, it turns into a protein. Peptides and proteins represent a wide world of possibilities, and many molecular biologists spend years researching the functions of single peptides and proteins to learn more about how the body works.

When discussing peptides, a lot of scientific terminology tends to get thrown around, and it can help to know what various terms mean. A covalent bond is a type of chemical bond which occurs when atoms share electrons. The specific type of covalent bond formed in peptides is known as a peptide bond or amide bond, and it forms when the carboxyl group of one amino acid attaches to another. Carboxyl groups are clusters of carbon, oxygen, and hydrogen molecules, in case you're curious.

The classification of a peptide as a polymer is sometimes confusing to people who are not familiar with this use of the term “polymer.” While many people mean “plastics” when they talk about polymers, in chemistry, a polymer is any sort of repeating chain connected with covalent bonds. Polymers can get extremely complex, as one might imagine.
A peptide can perform a wide range of functions in the body, depending on which amino acids are involved. Some can regulate hormones, for example, while others can have an antibiotic function. The body is also equipped to break down and reuse peptides; if you eat meat, for example, the enzymes in your intestines break down the protein at its amide bonds to create an assortment of peptides which may be digested or excreted, depending on the needs of your body.

The dividing line between a peptide and a protein is somewhat fluid. Proteins are much more complex than peptides, because they are so much longer, and most proteins are folded into complex structures to accommodate all of their amino acids. As a general rule of thumb, if more than 50 amino acids are involved, the compound is a protein, while shorter chains are considered peptides.

This next piece is something that I co-wrote for the company that I’m consulting with now called Helix BioMedix. We wrote this piece to accompany Striking, the line that we just launched that contains SmartPeptides™. It tells you specifically what SmartPeptides™ will do for the skin. It’s also important to note that these peptides are in the product at efficacious percentages, which means, we put in enough so that it will work, where as some companies put it just a tiny amount for a marketing claim (this happens more often than you think).
What is a peptide?
A peptide is a chain of two or more amino acids. The amino acids that make up a peptide can be sequenced in a particular order that will stimulate different responses within the body by landing on key cell receptor sites and communicating a specific function or task to the cell.
Helix BioMedix’s SmartPeptides™ are sequenced to stimulate the skin’s own natural protection and repair functions. Think of them as tiny messengers sent to kick the skin into gear and make it look better. Some of the SmartPeptides stimulate collagen production while others help restore keratinocytes. Let’s take a look:

Heptapeptide-7 is the latest advance in peptide technology from Helix BioMedix. This bioactive peptide has been shown to promote keratinocyte proliferation and migration to support skin renewal.

Palmitoyl Hexapeptide-14 boosts collagen production thereby reducing the appearance of wrinkles and increasing firmness of the skin.

Hexapeptide-21 works deep within the skin to stimulate the skin’s own natural repair and regeneration system. Tests have shown that this peptide controls visible signs of photoaging while calming the skin.

There are a few other peptides on the market that I’m either fond of, or that you’ve heard of like the copper peptide family that includes Prezatide Copper Acetate and Copper Tripeptide-1 (check out my blog for 10/17/08 for more information), Matrixyl aka palmitoyl pentapeptide-4 (for more info go to http://www.crodausa.com/, click on “new search” and type “matrixyl” in the search box) and Argireline aka acetyl hexapeptide-3 (which claims to be a topical wrinkle relaxer, think “topical botox”).

If you have more questions about peptides or want me to dig deeper, let me know! And Deb, sorry. Your request for an explanation of peptides in 50 words or less got a little bit out of control. I kept it under 1000, do I get points for that????