Biochemistry: Reactions of amino acids (Part-1)
Summary
TLDRThis video explores the chemical reactions of amino acids, focusing on those involving both the amino and carboxylic groups. It covers salt formation, peptide bond synthesis, ester and amino acyl chloride formation, decarboxylation, and amide formation. The explanation includes laboratory synthesis techniques and the reactions' underlying mechanics.
Takeaways
- 🧬 Amino acids are organic biomolecules with two oppositely charged functional groups, an amino group and a carboxylic group, attached to the same carbon atom.
- 🌐 Amino acids exist in a zwitterion form, where the amino group is protonated and the carboxylic group is deprotonated.
- 🔗 The chemical reactions of amino acids can involve both the amino and carboxylic groups or be due to one group alone.
- 🧂 Salt formation is a reaction where amino acids react with acids or bases to form salts, such as the chloride salt with hydrochloric acid.
- 🤝 Peptide bond formation is a key reaction involving both the amino and carboxylic groups of different amino acids, leading to the formation of proteins.
- 🧪 Laboratory synthesis of peptide bonds involves the use of phosgene to create an active residue that polymerizes to form peptide chains.
- 🍾 Ester formation is a reaction where amino acids react with alcohol in the presence of dry HCl to form esters, which can be reduced to alcohols.
- 🧪 Amino acyl chlorides are formed by acetylating and then treating amino acids with PCl5, followed by removal of the acetyl group with HCl.
- ♨️ Decarboxylation is a reaction where amino acids lose carbon dioxide upon heating with barium hydroxide or diphenylamine, resulting in amines.
- 🍀 Amide formation involves treating amino acid esters with ammonia to produce amides, as demonstrated with the preparation from amino acid esters.
- 📚 The video promises a follow-up to explain reactions occurring exclusively due to the involvement of the amino group of amino acids.
Q & A
What are amino acids and what makes them unique?
-Amino acids are organic biomolecules that contain two oppositely charged functional groups, an amino group and a carboxylic group, covalently bonded to the same carbon atom. They are unique because they can participate in various chemical reactions due to these functional groups.
What is the significance of the amino group and carboxylic group in amino acids?
-The amino group is positively charged and the carboxylic group is negatively charged. These groups are significant as they allow amino acids to engage in various chemical reactions, including salt formation, peptide bond formation, and others.
What is the zwitterion form of an amino acid?
-The zwitterion form is when the amino group gets protonated and the carboxylic group gets deprotonated, resulting in a molecule with both positive and negative charges.
How do amino acids form salts with acids and bases?
-Amino acids form salts when they react with acids like hydrochloric acid to form chloride salts, or with bases like sodium hydroxide to form sodium salts, with the loss of a water molecule.
What is a peptide bond and how is it theoretically formed?
-A peptide bond is a linkage formed between the amino group of one amino acid and the carboxylic group of another. Theoretically, it is formed when two amino acids fuse and their respective functional groups react with each other.
Can you describe the laboratory synthesis of a peptide bond?
-In the laboratory, an amino acid is heated with phosgene to yield an active residue, which polymerizes to form a peptide chain. The active residues react with each other to form the peptide bond.
What is the purpose of the ester formation reaction in amino acids?
-Ester formation is a reaction where an amino acid reacts with an alcohol in the presence of dry HCl to form an ester. This reaction is used to study and modify the properties of amino acids.
How are amino acyl chlorides formed from amino acids?
-Amino acyl chlorides are formed by first acetylating the amino acid for protection, then treating it with PCl5, and finally removing the acetyl group with HCl to yield the amino acyl chloride.
What is decarboxylation and how does it relate to amino acids?
-Decarboxylation is a reaction where an amino acid, when heated in the presence of barium hydroxide or diphenylamine, loses carbon dioxide and forms an amine. For example, histidine decarboxylates to form histamine.
How can amino acid amides be prepared?
-Amino acid amides can be prepared by treating amino acid esters with alcoholic or anhydrous ammonia, which yields the corresponding amino acid amide.
What will be discussed in the next video by the same channel?
-The next video will explain the reactions of amino acids that occur exclusively due to the involvement of the amino group.
Outlines
🧬 Introduction to Amino Acid Reactions
This paragraph introduces the topic of amino acid reactions in biochemistry. Amino acids are organic biomolecules with two oppositely charged functional groups (an amino group and a carboxylic group) covalently bonded to the same carbon atom. These groups participate in various chemical reactions, such as salt formation, peptide bond formation, ester formation, amino acyl chloride formation, decarboxylation, and amide formation. The video will focus on reactions involving both the amino group and the carboxylic group, starting with salt formation and peptide bond formation. The theoretical and laboratory synthesis of peptide bonds are also discussed, highlighting the process of linking amino acids through a covalent bond.
🧪 Reactions Involving Carboxylic Group and Both Groups
This paragraph delves deeper into the reactions of amino acids, focusing on those involving the carboxylic group and both the amino and carboxylic groups. Ester formation is explained, where amino acids react with alcohol in the presence of dry HCl to form esters. Amino acyl chlorides are formed by acetylating the amino acid and then treating it with PCL5, with the acetyl group being removable by HCl. Decarboxylation is discussed, where heating an amino acid in the presence of barium hydroxide or diphenylamine results in the loss of carbon dioxide and the formation of an amine. Finally, amide formation is described, where amino acid esters are treated with alcoholic or anhydrous ammonia to yield amino acid amides. The video promises to cover reactions involving the amino group in a subsequent video, and references are provided for further information.
Mindmap
Keywords
💡Amino Acids
💡Amino Group
💡Carboxylic Group
💡Zwitterion
💡Salt Formation
💡Peptide Bond
💡Ester Formation
💡Amino Acyl Chlorides
💡Decarboxylation
💡Amide Formation
💡Sanger's Reagent
Highlights
Amino acids are organic biomolecules with two oppositely charged functional groups, an amino group and a carboxylic group, covalently bonded to the same carbon atom.
Amino acids exist as zwitterions, where the amino group is protonated and the carboxylic group is deprotonated.
Amino acids participate in various chemical reactions, including salt formation, peptide bond formation, ester formation, and more.
Salt formation occurs when amino acids react with acids or bases, leading to the formation of salts such as the chloride salt with hydrochloric acid.
Peptide bond formation is a key reaction involving both the amino and carboxylic groups of different amino acids, creating a covalent linkage.
Laboratory synthesis of peptide bonds involves heating amino acids with phosgene to form an intermediate that polymerizes into a peptide chain.
Ester formation is a reaction where amino acids react with alcohol in the presence of dry HCl to form esters.
Amino acyl chlorides are formed by acetylating and then treating amino acids with PCl5, followed by removal of the acetyl group with HCl.
Decarboxylation is a reaction where amino acids lose carbon dioxide when heated in the presence of certain compounds, forming amines.
Amide formation involves treating amino acid esters with alcoholic or anhydrous ammonia to yield amides.
The video discusses reactions due to the involvement of both the amino and carboxylic groups, as well as those due to the carboxylic group alone.
The theoretical representation and laboratory synthesis of peptide bonds are explained, highlighting the complexity of the process.
Ester formation is detailed, including the role of dry HCl in breaking the zwitterion structure to form amino acid hydrochloride.
Amino acyl chlorides are shown to be intermediates in the protection and activation of amino acids for further reactions.
Decarboxylation is exemplified by the conversion of histidine to histamine, demonstrating a specific application of the reaction.
Amide formation is described as a two-step process starting from amino acid esters and involving the use of ammonia.
The video promises a follow-up to explain reactions occurring exclusively due to the involvement of the amino group.
Previous videos and references are mentioned for further information on amino acid structure and properties.
The video is prepared by Dr. Dre Pauline Goswami, providing credibility and专业性 to the content.
Transcripts
welcome to my youtube channel learn at
ease in this video I will discuss a
topic in biochemistry where I will
explain reactions of amino acids this is
part 1 video amino acids are the group
of organic biomolecules that possess two
oppositely charged functional groups
covalently bounded to same carbon atom
these two functional groups are one
amino group which is positively charged
two carboxylic group which is negatively
charged amino acid exists as video Ryan
where amino group gets protonated and
carboxylic group gets deprotonated the
amino group and the carboxylic group in
the amino acids participate in several
chemical reactions which will be
discussed in this video reactions of
amino acid can be due to involvement of
both amino group and carboxylic group or
reactions can be purely due to
involvement of carboxylic group or
reactions can be purely due to
involvement of amino group salt
formation with acid and base and
formation of peptide bond are the
reactions of amino acids due to
involvement of both amino group and
carboxylic group formation of ester
formation of amino acyl chlorides
decarboxylation and amide formation are
the reactions of amino acids purely due
to involvement of carboxylic group
oscillation Venza will Asian methylation
reaction with Sanger's reagent reaction
with hno2 oxidative deamination reaction
with formaldehyde reaction with aldehyde
reaction with ninhydrin reaction with
carbon dioxide and viet reaction are the
reactions of amino acids purely due to
involvement of amino group in this video
I will be describing reactions purely
due to involvement of carboxylic group
and reactions due to involvement of both
amino group and carboxylic group of
amino acid
I will start by describing reactions of
amino acids due to involvement of both
amino group and carboxylic group the
first reaction is salt formation amino
acids form salts with acid and bases
amino acid when reacts with acid such as
hydrochloric acid it forms the chloride
salt of amino acid similarly when amino
acid when reacts with base such as
sodium hydroxide it forms sodium salt of
amino acid with a loss of water molecule
now let's see the second reaction that
is formation of peptide bond the
theoretical representation of peptide
bond formation shows that when two
molecules of amino acid are fused the
amino group and the carboxylic group of
two different amino acids reacts with
each other and forms a co and H linkage
this linkage formed between amino group
and the carboxylic group is called
peptide bond this is the theoretical
representation of peptide bond formation
however the laboratory synthesis of
peptide bond is not so simple I will now
explain the laboratory synthesis of
peptide bond formation between two amino
acids laboratory synthesis of peptide
bond is described here amino acid is
heated with phosgene to yield and
carboxy amino acid and hydride and
carboxy amino acid and hydride is stable
only below 10 degrees Celsius when n
carboxy amino acid and hydride is heated
in dry state it splits out co2 and leave
out its active residue active residue is
NH CHR SIA
this active residues polymerized to form
large peptide chain the image below
shows the active residues react with one
another and forms a short peptide chain
and the linkage between two amino acid
that is the peptide bond is formed now I
will explain reactions of amino acids
purely due to involvement of carboxylic
group here the first reaction is
formation of ester the reaction
described
the formation of amino acid ester in the
reaction amino acid reacts with alcohol
in presence of dry HCl to give
corresponding ester HCL first breaks up
Vitara in structure to form amino acid
hydrochloride amino acid hydrochloride
then reacts with alcohol the ester
hydrochloride is decomposed by mild
alkali in cold to give free ester both
free amino acids and their esters are
readily reduced by lithium aluminium
hydride dissolved in ether to the
corresponding alcohols without rihanna's
ation carefully see the reactions to
understand the mechanics now I will
explain the second reaction that is
formation of amino acyl chlorides the
reaction described shows the formation
of amino acyl chlorides from amino acid
the amino acid is first acetylated for
protection a set elated amino acid is
then treated with PCL 5 the acetyl group
may be removed by treatment with HCl the
amino acyl chlorides exists at
hydrochloride salts carefully see the
reactions and the intermediates form to
understand the mechanics of reaction now
I will explain the third reaction that
is decarboxylation the amino acid when
heated in presence of barium hydroxide
or diphenylamine carbon dioxide is lost
and amine is formed decarboxylation of
histidine is shown in below where it
gets converted to histamine now I will
explain the fourth and the last reaction
that is amide formation the amino acid
amides may be prepared by treatment of
amino acid esters with alcoholic or
anhydrous ammonia the starting compound
for this reaction is amino acid ester
which is formed from amino acid the
formation of amino acid esters is
described earlier in this video which
when treated with alcoholic or anhydrous
ammonia yields amino acid amide
carefully see the reaction to understand
the mechanics of reaction in my next
video I will explain the reaction
of amino acids exclusively occurring by
the involvement of amino group for more
information on amino acid structure and
properties see my previous videos links
to these videos are provided in the
description stay tuned to my channel
references used to prepare this video
are given here if you are new to my
channel please subscribe below thank you
for watching my video this video is
prepared by dr. Dre Pauline Goswami
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