Just started wondering.

Proteins are polymerised using the “condensation reaction” (ie water loss) from amino acids.

It’s generally said tgat this water loss occurred by evaporation of the primordial soup, but i’ve never been completely convinced.

Since many commercial polymers are produced by the condensation reaction without relying on evaporation I’ve wondered how they do it.

I only just realised that bakelite is made by the condensation reaction. It’s polymerised trom phenol and formaldehyde in the presence of a catalyst. One such catalyst is ammonia, which used to be almost as common as water. Following on that thought, ammonia, phenol and formaldehyde could all have been present in the primordial soup. So bakelite and proteins could have existed side by side on the proto-Earth.

The key thing here for me is the use of ammonia in polymerising amino acids into proteins, without necessarily any evaporation.

mollwollfumble said:

Just started wondering.

Proteins are polymerised using the “condensation reaction” (ie water loss) from amino acids.

It’s generally said tgat this water loss occurred by evaporation of the primordial soup, but i’ve never been completely convinced.

Since many commercial polymers are produced by the condensation reaction without relying on evaporation I’ve wondered how they do it.

I only just realised that bakelite is made by the condensation reaction. It’s polymerised trom phenol and formaldehyde in the presence of a catalyst. One such catalyst is ammonia, which used to be almost as common as water. Following on that thought, ammonia, phenol and formaldehyde could all have been present in the primordial soup. So bakelite and proteins could have existed side by side on the proto-Earth.

The key thing here for me is the use of ammonia in polymerising amino acids into proteins, without necessarily any evaporation.

Reasonable.

Michael V said:

mollwollfumble said:

Just started wondering.

Proteins are polymerised using the “condensation reaction” (ie water loss) from amino acids.

It’s generally said tgat this water loss occurred by evaporation of the primordial soup, but i’ve never been completely convinced.

Since many commercial polymers are produced by the condensation reaction without relying on evaporation I’ve wondered how they do it.

I only just realised that bakelite is made by the condensation reaction. It’s polymerised trom phenol and formaldehyde in the presence of a catalyst. One such catalyst is ammonia, which used to be almost as common as water. Following on that thought, ammonia, phenol and formaldehyde could all have been present in the primordial soup. So bakelite and proteins could have existed side by side on the proto-Earth.

The key thing here for me is the use of ammonia in polymerising amino acids into proteins, without necessarily any evaporation.

Reasonable.

I’m finding it difficult to find on the web any information on what catalysts can be used for condensation polymerisation, and why they work. The wikipedia article on bakelite mentions hydrochloric acid, zinc chloride, and ammonia as catalysts. But it’s not even clear whether that’s the catalyst for the condensation reaction or for the reaction of phenol and formaldehyde. :-(

Michael V said:

mollwollfumble said:

Just started wondering.

Proteins are polymerised using the “condensation reaction” (ie water loss) from amino acids.

It’s generally said tgat this water loss occurred by evaporation of the primordial soup, but i’ve never been completely convinced.

Since many commercial polymers are produced by the condensation reaction without relying on evaporation I’ve wondered how they do it.

I only just realised that bakelite is made by the condensation reaction. It’s polymerised trom phenol and formaldehyde in the presence of a catalyst. One such catalyst is ammonia, which used to be almost as common as water. Following on that thought, ammonia, phenol and formaldehyde could all have been present in the primordial soup. So bakelite and proteins could have existed side by side on the proto-Earth.

The key thing here for me is the use of ammonia in polymerising amino acids into proteins, without necessarily any evaporation.

Reasonable.

I’m finding it difficult to find on the web any information on what catalysts can be used for condensation polymerisation, and why they work. The wikipedia article on bakelite mentions hydrochloric acid, zinc chloride, and ammonia as catalysts. But it’s not even clear whether that’s the catalyst for the condensation reaction or for the reaction of phenol and formaldehyde. :-(

Link for further study 98 Improved base catalysts for industrial condensation reactions but, what’s an aldol?

“An aldol condensation is a condensation reaction in organic chemistry in which an enol or an enolate ion reacts with a carbonyl compound to form a β-hydroxyaldehyde or β-hydroxyketone (an aldol reaction), followed by dehydration to give a conjugated enone.”

Crystal clear? Not.

mollwollfumble said:

Proteins are polymerised using the “condensation reaction” (ie water loss) from amino acids.

It’s generally said tgat this water loss occurred by evaporation of the primordial soup, but i’ve never been completely convinced.

Peptide bonds won’t form simply by the evaporation of amino acids. Heat is required, at a guess, around 150°C – 200°C. However, it is generally accepted that the principle dehydrating agents of the primordial earth are polyphosphate minerals. Evidence of this is that living organisms continue to use polyphosphate compounds as dehydrating agents.

mollwollfumble said:

I’m finding it difficult to find on the web any information on what catalysts can be used for condensation polymerisation, and why they work. The wikipedia article on bakelite mentions hydrochloric acid, zinc chloride, and ammonia as catalysts. But it’s not even clear whether that’s the catalyst for the condensation reaction or for the reaction of phenol and formaldehyde. :-(

The reaction of phenol with formaldehyde to form phenol formaldehyde resin (Bakelite) is an example of an electrophilic aromatic substitution, with formaldehyde as the electrophile reacting with phenol as a very reactive aromatic compound. It is catalysed by both acid and base. Acid catalysis activates the formaldehyde, whereas base catalysis activates the phenol. The formaldehyde attacks the _ortho_- and _para_- positions of the phenol.

KJW said:

The formaldehyde attacks the _ortho_- and _para_- positions of the phenol.

The formaldehyde attacks the ortho- and para- positions of the phenol.

mollwollfumble said:

Link for further study 98 Improved base catalysts for industrial condensation reactions but, what’s an aldol?

“An aldol condensation is a condensation reaction in organic chemistry in which an enol or an enolate ion reacts with a carbonyl compound to form a β-hydroxyaldehyde or β-hydroxyketone (an aldol reaction), followed by dehydration to give a conjugated enone.”

Crystal clear? Not.

Welcome to organic chemistry.

KJW said:

mollwollfumble said:

Proteins are polymerised using the “condensation reaction” (ie water loss) from amino acids.

It’s generally said tgat this water loss occurred by evaporation of the primordial soup, but i’ve never been completely convinced.

Peptide bonds won’t form simply by the evaporation of amino acids. Heat is required, at a guess, around 150°C – 200°C. However, it is generally accepted that the principle dehydrating agents of the primordial earth are polyphosphate minerals. Evidence of this is that living organisms continue to use polyphosphate compounds as dehydrating agents.

Hey thanks. Didn’t know that. 150°C – 200°C ie well above the boiling point of water, but not out of the question on a primitive Earth.

Interesting that you’ve said polyphosphate rather than phosphate. I know phosphate minerals. Polyphosphates form by condensation (water loss) from phosphates. So are you saying that polyphosphate break up into phosphates absorbs water allowing amino acids to combine into proteins? Or is it more complicated than that?

mollwollfumble said:

Interesting that you’ve said polyphosphate rather than phosphate. I know phosphate minerals. Polyphosphates form by condensation (water loss) from phosphates. So are you saying that polyphosphate break up into phosphates absorbs water allowing amino acids to combine into proteins? Or is it more complicated than that?

The carboxylate anion of the amino acid performs a nucleophilic substitution on the phosphorus atom of a phosphate unit, with the adjacent phosphate group as the leaving group. This activates the acyl group as the acyl phosphate, which reacts with the amino group acting as the nucleophile to form the peptide bond with phosphate as the leaving group. Ultimately, the water molecule that would be formed when the peptide bond is formed hydrolyses the P–O bond between two phosphate groups of the polyphosphate. But no water molecule sees the light of day.

It’s worth noting that ATP (adenosine triphosphate) delivers its stored energy in the form of dehydration.

KJW said:

It’s worth noting that ATP (adenosine triphosphate) delivers its stored energy in the form of dehydration.

Interestingly, cells get their energy from redox reactions, and to convert this form of energy to dehydration energy is actually very difficult. The difficulty of this conversion is highlighted by the technique used by mitochondria known as oxidative phosphorylation where a physical hydrogen ion concentration gradient is used to couple the electron transport chain to the phosphorylation of adenosine diphosphate to adenosine triphosphate.

KJW said:

mollwollfumble said:

Interesting that you’ve said polyphosphate rather than phosphate. I know phosphate minerals. Polyphosphates form by condensation (water loss) from phosphates. So are you saying that polyphosphate break up into phosphates absorbs water allowing amino acids to combine into proteins? Or is it more complicated than that?

The carboxylate anion of the amino acid performs a nucleophilic substitution on the phosphorus atom of a phosphate unit, with the adjacent phosphate group as the leaving group. This activates the acyl group as the acyl phosphate, which reacts with the amino group acting as the nucleophile to form the peptide bond with phosphate as the leaving group. Ultimately, the water molecule that would be formed when the peptide bond is formed hydrolyses the P–O bond between two phosphate groups of the polyphosphate. But no water molecule sees the light of day.

It’s worth noting that ATP (adenosine triphosphate) delivers its stored energy in the form of dehydration.

Interestingly, cells get their energy from redox reactions, and to convert this form of energy to dehydration energy is actually very difficult. The difficulty of this conversion is highlighted by the technique used by mitochondria known as oxidative phosphorylation where a physical hydrogen ion concentration gradient is used to couple the electron transport chain to the phosphorylation of adenosine diphosphate to adenosine triphosphate.

> when the peptide bond is formed hydrolyses the P–O bond between two phosphate groups of the polyphosphate. But no water molecule sees the light of day. ATP (adenosine triphosphate) delivers its stored energy in the form of dehydration.

Thanks for clearing that up.

> Interestingly, cells get their energy from redox reactions, and to convert this form of energy to dehydration energy is actually very difficult.

Is this a two step process?

ie. does the energy from redox reactions first get stored as membrane potentials (like those used to fire nerve cells, but ubiquitously). And then the membrane potentials get converted into ATP. Or is it more direct than that?

mollwollfumble said:

> Interestingly, cells get their energy from redox reactions, and to convert this form of energy to dehydration energy is actually very difficult.

Is this a two step process?

ie. does the energy from redox reactions first get stored as membrane potentials (like those used to fire nerve cells, but ubiquitously). And then the membrane potentials get converted into ATP. Or is it more direct than that?

I had not seen the H ion concentration gradient across the inner mitochondrial membrane described as a “membrane potential”, but apparently there is a voltage across the membrane, though it is the concentration gradient that drives the phosphorylation of ADP to ATP. The enzyme ATP synthase couples the transport of H ions across the membrane to the phosphorylation of an ADP molecule. The H ion concentration gradient is produced within the electron transport chain by the reduction of a quinone (ubiquinone, a.k.a. coenzyme Q₁₀) to the corresponding quinol on one side of the membrane, a reaction that absorbs two H ions, and the subsequent oxidation of the quinol back to the quinone on the other side of the membrane, releasing the two H⁺ ions that were previously absorbed.

mollwollfumble said:

KJW said:

Interestingly, cells get their energy from redox reactions, and to convert this form of energy to dehydration energy is actually very difficult.

Is this a two step process?

ie. does the energy from redox reactions first get stored as membrane potentials (like those used to fire nerve cells, but ubiquitously). And then the membrane potentials get converted into ATP. Or is it more direct than that?

I had not seen the H ion concentration gradient across the inner mitochondrial membrane described as a “membrane potential”, but apparently there is a voltage across the membrane, though it is the concentration gradient that drives the phosphorylation of ADP to ATP. The enzyme ATP synthase couples the transport of H ions across the membrane to the phosphorylation of an ADP molecule. The H ion concentration gradient is produced within the electron transport chain by the reduction of a quinone (ubiquinone, a.k.a. coenzyme Q₁₀) to the corresponding quinol on one side of the membrane, a reaction that absorbs two H ions, and the subsequent oxidation of the quinol back to the quinone on the other side of the membrane, releasing the two H⁺ ions that were previously absorbed.