The human brain produces polypeptides called endorpbins that...

The human brain produces polypeptides called endorpbins that help in controlling pain. The pentapeptide in Figure $\mathrm{P} 20.5$ is called enkephalin. Identify the five amino acids that make up enkephalin.
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Key Concepts

Opioid Peptides

Opioid peptides are a class of peptides that bind to opioid receptors in the nervous system. Their interactions help control pain and can influence mood and various physiological functions.

Enkephalin

Enkephalin is a specific example of an endogenous pentapeptide that plays a critical role in modulating pain. It is one of several opioid peptides produced naturally in the body to regulate pain perception.

Polypeptides

Polypeptides are chains of amino acids linked together by peptide bonds. They form the basic structure of proteins and can serve a variety of functions, including acting as hormones, enzymes, or structural components in cells.

Amino Acids

Amino acids are the fundamental building blocks of proteins. Each amino acid has a specific side chain, and the order of amino acids in a peptide or protein determines its structure and function.

Peptide Primary Structure

The primary structure of a peptide refers to the linear sequence of amino acids present in the molecule. This sequence dictates the peptide's overall shape, biological activity, and its interaction with other molecules.

Transcript

00:01 In this problem, we're given a structure, and we're told that there are five amino acids within the structure.

00:06 And we're asked to identify them.

00:09 So we're going to use this general structure of what an amino acid looks like to help us identify them.

00:17 For every amino acid, we're going to be looking for this central carbon atom, which is directly bonded to an amine group, hydrogen group, and a carboxylic acid group.

00:26 And for any of the amino acids that we find, those are not going to change.

00:32 What is going to change is this variable side chain r group, which is a unique identifier for a given amino acid.

00:40 If you haven't memorized the amino acids, it's helpful to solve this problem using a table so that once you identify that unique r group, you can easily look up and find which amino acid that corresponds to.

00:56 So that's the methodology we'll be using to go through the solution.

01:04 And this is the structure that's given in the problem.

01:08 And so we're going to be looking for that central carbon atom so that we can identify all five amino acids.

01:15 First, we see a carboxylic acid group and amine group here that are directly bonded to this carbon atom, making it a central carbon atom or an amino acid, which means that this is that variable side chain that identifies the amino acid.

01:32 And when we look up in the table, that side chain corresponds to the amino acid methyanine.

01:41 So that is one of the five amino acids present in the structure.

01:47 So we'll go ahead.

01:49 We've identified it...

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