How to calculate the free amino and carboxyl groups in the peptide chain

Free means that it is not combined with the other parts. For a polypeptide chain, one end is an amino group and the other end is a carboxyl group.

Then in each amino acid.

There may be one or more carboxyl or amino groups on the R group, so it cannot be calculated directly. It can only be said that a polypeptide chain has at least one amino group and one carboxyl group.

The free carboxyl and amino groups are the carboxyl and amino groups that are not involved in the formation of peptide bonds.

Normally, a peptide chain will have a C-terminal (carboxyl terminus) and an N-terminus (amino terminus), one free carboxyl group and one free amino group respectively, and some kinds of amino acids also contain carboxyl groups or amino groups.

Then the total free amino and carboxyl groups are the sum of the above two.

Each amino acid has at least one amino group and one carboxyl group, but when amino acids combine with each other to form polypeptides, the carboxyl group of one amino acid and the carboxyl group of another amino acid are dehydrated to form a peptide bond, and the original amino group and carboxyl group at the junction do not exist, and the amino group and carboxyl group are only retained at both ends of the peptide chain, so if there is no excess amino group and carboxyl group in the middle, generally a peptide chain only retains an amino group at this end and a carboxyl group at the other end.

Each peptide chain has a free amino and carboxyl group, plus the number of amino and carboxyl groups on the R group is the sum of them. For example, if there are 2 amino groups and 1 carboxyl group on the R group, then there are 3 (2+1) on this peptide chain.

It is an amino and carboxyl group that does not form peptide bonds with other groups. In general, a straight polypeptide has a free amino group and a free carboxyl group, i.e., one has a beginning and one at the end.

There is a complete structure -NH2, -COOH, which are all free, and -NH-c=O- which is in the peptide bond, it is not free.

A peptide chain has at least 1 amino and carboxyl group. The number of amino or carboxyl groups contained in a protein molecule should be seen by the number of peptide chains, and if there are several peptide chains, there are at least a few amino groups or several carboxyl groups, and a peptide chain contains at least 1 free amino group and 1 free carboxyl group.

Carboxy is the basic chemical group in organic chemistry, and all organic acids containing carboxyl groups can be called carboxylic acids, which are composed of one carbon atom, two oxygen atoms and one hydrogen atom, with the chemical formula -COOH. For example, acetic acid (CH3-COOH) and amino acids contain carboxyl groups, and these carboxyl groups are directly linked to the hydrocarbon groups, which are called carboxylic acids.

First for a peptide chain.

There can only be three positions in n, one is that there must be one at the end of the peptide chain, and the other is the peptide bond in the peptide chain.

Another possibility of co-nh--, is r--

When doing the question, you only need to take these three analyses.

For example, this trace peptide chain contains 10 N, so after deducting the amino group at the beginning and end, there are 9 n left.

Regardless of the R group, there are up to 9 peptide bonds.

Then according to the formula number of amino groups - number of peptide chains = = number of peptide bonds to get amino acids.

10 pcs.

If a peptide chain is formed, it is called M peptide.

Number of dehydrations = number of peptide bonds = number of amino acids - number of peptide chains.

The calculation formula for the number of amino acid socks and socks is good for burning.

Number of peptide bonds = number of water molecules removed.

Number of amino acids, number of peptide chains, number of peptide skin spring bonds.

Peptide bonds. Put the amino acids adjacent to the front and back.

so that the number of peptide bonds in the peptide chain is always one less than the number of amino acids, that is, the number of peptide bonds in the peptide chain of n amino acids is equal to n-1

If a protein contains n peptide chains and m amino acids, the number of peptide bonds is equal to m-n

Regardless of cyclic polypeptides, if there are n amino acids in a chain, then the number of peptide bonds is n-1

Then the two chains are 2n amino acids, then the number of peptide bonds is (n-1) 2=2n-2 and the three chains are 3n amino acids, then the number of peptide bonds is (n-1) 3=3n-3a chains are an amino acid, then the number of peptide bonds is (n-1) a=an-a, and the number of peptide bonds = the number of amino acids - the number of chains.

Or to put it another way, every chain has an amino terminus and a carboxyl terminus. A locust amino group and a carboxyl group can basically form a peptide bond, and one more sprocket hand is equivalent to one less pair of amino groups and carboxyl groups to form peptide chuntong friend bonds, so the number of chains should be reduced.

nh2-rch-co-hn-rch-co-hn-rch-co-hn-……c-cooh

Suppose this is a peptide chain and does not consider the R-group of each amino acid, then it has a free amino and carboxyl group at each end.

One more peptide chain adds one more free amino and carboxyl group.

I don't know if you understand ...... when I say that

If you don't understand, you can continue to ask me, saying that you studied biology in your first year of high school?

Hope it helps

The general formula of amino acid structure is like this.

One of the peptide chains formed by dehydration and condensation is as follows.

No matter how long the peptide chain is, there are always two ends, one end is the amino group in No. 2, and the other end is the No. 9 carboxyl group, which means that a peptide chain has at least these two free amino and carboxyl groups.

Then look at box 6 and 8, there is also a carboxyl group in each box, and these carboxyl groups belong to the r group, so there are a total of 1 free amino group and 3 free carboxyl groups in the whole peptide.

When there are no free amino and carboxyl groups in the R group, the number of peptide chains = number of ammonia = number of carboxyl groups will not be equal to the number of amino acids (a peptide chain should have at least 2 amino acids).

The problem of peptide bonds can be imagined as having n people holding hands and standing in a row, each person is an amino acid, and every two hands holding a peptide bond. This forms a peptide chain. Then the peptide bond number is n 1, because the head and tail are not holding hands.

There is n=(n-1)+1. When two people in the chain let go of the holding hand, there is one less peptide bond, that is, one molecule of water is removed, but one more peptide chain is added. Let go of the pair of holding hands again, there is another peptide bond, another molecule of water is removed, and another peptide chain is added.

There is n=(n-2)+2. And so on, and you can find the pattern.

A polypeptide chain contains at least one free amino group and one free carboxyl group, because after multiple amino acids are dehydrated and condensed to form a polypeptide, two amino acids on both sides, one free and one amino group, and one free and one carboxyl. But there is another problem, there may be an amino group or a carboxyl group on the R group, so it is generally said that it contains at least one free amino group and one free carboxyl group.

If you understand this truth, your subsequent problems will no longer be a problem.

Because a polypeptide chain contains at least one free amino group and one free carboxyl group, the n polypeptide chain contains at least n free amino groups and n free carboxyl groups.

Creatures listen well. A peptide chain must have an amino group on the head and a carboxyl group on the tail, as for how many are in total, it is not clear, but a peptide chain contains at least one free amino group and one free carboxyl group. So there are at least as many amino and carboxyl groups as there are peptide chains.

As for those two formulas, it shouldn't be a problem to memorize them.

Because there may also be carboxyl and hydroxyl groups on the R group, it is at least.

Let's take an example: for example, if there are 20 amino acids forming a peptide chain, the number of dehydrated molecules is 19. Now two peptide chains are formed, one with 10 AA, then each peptide chain removes 9 water molecules, a total of 18 are removed, that is, 20 (aa number) -2 (peptide chain number) = 18

This will allow you to do the questions, but it will not allow you to know what it is, but not why it is so. You can think of it this way: the number of AA on each peptide chain is always 1 more than the number of water molecules removed, so there are several peptide chains, and the total number of AA is a few more than the number of water molecules removed.

An amino group and a carboxyl group strip a molecule of water to form an amino acid that forms a peptide bond.

The number of water molecules = the number of peptide bonds is fine, because the formation of a peptide bond produces one molecule of water!

The number of amino acids - the number of peptide chains = the number of dehydrated molecules is actually just a simple mathematical derivation process.

One. In the case of the formation of 1 peptide chain [the number of amino acids - 1 (number of peptide chains) = the number of dehydrated molecules] 1What is the approximate process of amino acids forming proteins?

2.The dehydration condensation reaction of two amino acids to form a dipeptide and the loss of several molecules of water?

3.Three amino acids are dehydrated and condensed, and how many molecules of water are lost?

4.What about the dehydration condensation reaction of n amino acids?

Two. In the case of the formation of n peptide chains [the number of amino acids - n (number of peptide chains) = the number of dehydrated molecules].

You've made the number one, and the problem will be solved.

How much do you qq, it's inconvenient to say here that some pictures can't be pasted here, and you can only post one here.