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Xelacik t1_j9aufd3 wrote

The pH of what? We have a wide range of pHs in our body. Do you mean our skin? Our skin is actually acidic, if just mildly so. Same with hair. Blood is slightly alkaline. Stomach is obviously acidic (stomach acid). Saliva and urine changes depending on diet. Gotta be more specific if you want a good scientific answer :)

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GreatbigHippo t1_j9bu1nz wrote

Take a human, stick it in a blender until all the bits blend together into a human smoothie, then measure the PH of that

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[deleted] t1_j9c9tkw wrote

[removed]

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stronkreddituser OP t1_j9b0kbv wrote

I see how vague my question is now lol. Primarily, I was asking why any part of the body made up of proteins would be alkaline, but now I know that it is not as simple as "amino acid = acidic pH".

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-Arke- t1_j9b5al5 wrote

For starters, the previous answer can give you a general idea of how things are. That said, amino acid doesn't mean acid (or basic either).

An amino acid is a chain wich has a NH2 (basic) on one extreme and COOH (acid) on the other. So the actual PH of every aminoacid will deppend on the rest of the molecule.

But still, the actual answer would have more to do with what you've been told than it has to do with this, which is more of an anecdotic piece of knowledge.

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aphilsphan t1_j9b8qyi wrote

To add a bit, an amino acid can and will protonate itself. So the COOH (carboxylic acid) group “loses” its hydrogen as an ion (called a proton by chemists because that’s what it is). This results in the pronation of the amine (NH2) group. So you’ve got COO- on one end and NH3+ on the other. This is the “zwitterion” form.

Lots of chemistry is learning the vocabulary because the vocabulary makes it easier to communicate quickly.

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911derbread t1_j9emepg wrote

Hey! I'm a doctor and a biochem nerd. Your blood pH is buffered by multiple systems, primarily bicarbonate, as well as lactate and phosphate compounds. That means that swings in the concentration of blood compounds (aspirin, or salicylic acid, for example, is an acid) don't cause significant changes. pH is also tightly controlled by your lungs and kidneys. Your lungs control the amount of CO2 in your blood, and therefore bicarb and carbonic acid content. Your kidneys also retain or excrete bicarb as needed. There are certain processes like lactic acid production, electrolyte abnormalities, and kidney or lung issues that can make you relatively acidic. However, a truly acidic pH of even slightly less than 7 is a pretty profound acidosis and likely life threatening.

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GypsyV3nom t1_j9awfn7 wrote

The "acid" in amino acids refers to the carboxylic acid on the C-terminal side of the backbone, but doesn't actually mean the amino acid has acidic properties, it's just a naming convention. Most amino acids balance out around 7 because in water, the carboxylic acid will give up a proton while the N-terminus snags a proton. The net change in pH is thus largely negligible.

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LivingDegree t1_j9fmlj1 wrote

Piggybacking: There are also amino acids that are fairly basic (lysine, arginine, histidine); the properties of an amino acid (ie its pH) is largely determined by what’s going on with the amino acid itself (the actual aminal) instead of the C-terminus or N-terminus.

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aTacoParty t1_j9axl9r wrote

The name amino acid refers to the amine group (NH2-R) and the carboxylic acid group (COOH-R) that make up the backbone of amino acids. The amine group can be a proton acceptor while the carboxylic group can be a proton donator so most amino acids are neutral. Some amino acids have acidic R groups (gutamate/asparatate) which makes them acidic, while others have basic R groups (lysine, histidine, arginine) which makes them basic.

In reality, since proteins are made up of 100's or 1000's of amino acids, they act as buffers, accepting and donating protons as needed in the blood. However, protein isn't the main buffer used to maintain the blood pH. Our bodies need blood to be kept at ~7.4 pH in order to function and if that changes too much we can get really sick. Our blood uses carbonic acid/bicarbonate as its main buffer which provides stability to the blood pH.

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stronkreddituser OP t1_j9ayzil wrote

So, from my understanding of what you wrote, amino acids have both basic and acidic properties due to the presence of a basic amine and an acidic COOH as functional groups (other than the variable R group)... Although it is ultimately the buffers in our blood that are largely responsible for maintaining a pH of ~7.4.

Thanks for the detailed explanation!!

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aTacoParty t1_j9b2454 wrote

100% correct!

And since carbonic acid/bicarb is the main buffer in blood, we regulate that by regulating our breathing. CO2 is converted into carbonic acid so by holding our breath (or breathing slower), we retain CO2 and decrease blood pH. Inversely, by breathing faster we blow out more CO2 and increase our blood pH.

Decreased blood pH is one of the main drivers for breathing. When you're swimming underwater and you start to feel the urge to breathe, it isn't lack of oxygen but rather the decreased blood pH from retained CO2 that your brain is sensing.

As a short aside, it's really bad for your blood to be more acidic OR more basic than ~7.4 pH. So when you see products claiming to "alkalinize" your body/blood for health, it's complete BS. Acids and bases are not inherently bad or good just like how hot and cold things are not inherently bad or good. I see these ads pop up pretty frequently, especially in fitness related settings and it drives me nuts.

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BeneficialWarrant t1_j9b4rem wrote

1: Amino acids contain both an organic acid and organic base.

2: The acid and base are both neutralized in the process of making a protein.

3: Some amino acids remain acidic or basic after becoming part of a protein because of extra parts they have on a side chain (sort of like a pendant or charm hanging down from a necklace).

4: Excess acid in the body is is neutralized by carbonate which can then be converted to CO2 and exhaled or filtered out by the kidneys into urine. There is baking soda in your blood and you can't survive without it.

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Busterwasmycat t1_j9bbltc wrote

Acids come in different strengths so the amount of H+ that can be released relative to the total concentration of the acid compound is highly variable. Basically, the idea is that "acid" means that there is a favorable condition for releasing an H+ from the rest of the compound. Water is an acid, even. Its pH is 7. It isn't a very strong acid (hardly lets go of the H+ unless really forced to). Some acids, like HCl, though, have almost no hold on the H+ and will lose it easily, and acidify water a lot.

All by itself, the pH of water will be (about) 7, what we call neutral. Very weak acids tend to be made from strong bases (strong bases GRAB loose H+ if it is around), and strong acids when combined with strong bases, tend to make salts and water (like HCl (strong acid) reacts with NaOH (strong base) to make H2O (water) and NaCl (table salt); a solution with a near neutral pH).

In the bulk mix of compounds that is the natural world, and the human body too, the mixture of strong acids, weak acids, strong bases, and weak bases, and other things with effectively no acid behavior at all, when all the competition is done between the various species for grabbing or releasing an H+, the system tends to end up somewhere around neutral. The system "wants" to go to neutral if it can, basically. Strong bases grab H+ just as much as strong acids release it. The end balance in most systems sees this happen, and near-neutral is the result (just as likely to see a strong base as a strong acid, and the two coming together makes a neutral salt and water).

That is the basic reason that the human body is slightly above neutral in pH. It is mimicking (trying to reproduce) the natural world, the ocean that life came from or developed in, originally, which is slightly basic too.

What is an amino acid? They are basically ammonia (NH3) where the H atoms have been replaced, at least in part, by some other large chemical group, many of which are weak acids. We call such compounds "amines" (hence they make "amino" acids), because the nitrogen is in the reduced state (filled to max with electrons, hasn't met other elements that want its electrons even more than it does itself). When reduced nitrogen does meet a strong electron grabber like oxygen, it makes nitrates (and nitrites, sort of the same thing), but that is a little off where I am going with this explanation.

The amine groups tend to be attached to weakly acidic other compounds, or rather weak acids like HCO3-, so one side of the compound is a weak acid, but the other side, or sometimes inside (if all H+ has been replaced by weak acids), it is a strong base. So, because the primary characteristic is a weak acid, the compounds are "amino acids". However, they are not strong acids at all, they are weak acids and do not lower pH by much. If they had been stronger acids, they would have reacted with ammonia to make NH4+ (would have just told ammonia, here is the H+, take it and leave us alone out here in weak base land away from you).

Amino acids are, in effect, the result of that pH-balancing process that happens in nature. The amine group is, if in its normal state of ammonia (NH3), a very strong base. It wants to make NH4+ by grabbing any H+ it can find. the end result is that it sort of does do that, by grabbing on to other compounds that have a weak grasp on an H+, changing the product into a very weak acid rather than its once powerful base. When together, these combined molecules are pretty "happy" in near-neutral conditions. The strong base (ammonia) was neutralized by reacting with acids (like carbonic acid) and now we have a happy "acid" that is not very acidic in behavior, it is very weak. And there are still some bases out there floating around, not strong enough to grab H+ from the weak amino acids, but plenty strong enough to grab H+ from some stronger acids, if they come along, and in so doing, neutralizing them.

So, the system is happy and near neutral. It is where things, taken all together, tend to go to be in balance, somewhere near neutral pH. The world likes to get into some sort of middle balance if it can.

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AChristianAnarchist t1_j9crnai wrote

Well, you are focusing on the "acid" part of amino acid, rather than the "amino" part. The term amino acid comes from the fact that the backbone is made up of an amino group (normally basic) and a carboxyl group (normally acidic). However, none of that really matters at the end of the day since the vast majority of an amino acids properties derive from their side chains, not their backbone.

Side chains are what make the 20 amino acids different from eachother. Some are basic, some are acidic, some are polar, others nonpolar. While we don't fully understand the process, these properties are what allow a shape to be derived from an amino acid sequence. The particular properties of the side chains control what they are attracted and repelled by, which, in turn, determines how they fold in vivo. So a given protein is made up of basic and acidic bits, all folded up onto one another to produce a new molecule with its own emergent properties, which may, itself, be acidic or basic.

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CrateDane t1_j9awzq2 wrote

Amino acids have a carboxylic acid and an amino group, so it's both an acid and a base. In any case, once you dissolve it in water you can just add other acids or bases to change the pH.

Our DNA and RNA are also acidic, the A literally stands for acid. But again it's just buffered by other stuff.

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TheDentateGyrus t1_j9cc41w wrote

Tons of reasons. But specific to amino acids:

Proteins are amino acids in chains, not free floating individually. So ONE of the amino and carboxy groups are exposed to solute at either end of a given string of a peptide. The rest are hidden in peptide bonds. Also proteins are in 3D, we have buffers, and a ton of other things.

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Berkamin t1_j9ccxun wrote

Amino acids have a carboxylic acids group attached to a structure that also has an amine group. The amine group is basic. People hear the term "amino acid" and only recognize the acid part, but they are both acid and base. That is apparently how they get chained together. The charged amine group gets attracted to the charged carboxylate group and they stick together.

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green_print_business t1_j9e37ws wrote

That's a good question.... I'll explain it to you scientifically.
The human body has a natural system called acid-base balance that helps to keep the pH label stable. It is essential for the normal operation of biological processes. There are three major organs in our human body that help to regulate the balance. They are the liver, the kidneys, and the lungs. The PH of our bodies is 7.35-7.45 (as you mentioned). This means that our bodies are slightly alkaline. Our bodies have a variety of buffer systems made of various chemicals. These chemicals can absorb excess acid or base to maintain a normal ph level in the body.
One of the most important buffering systems in the body is the bicarbonate buffer system, which helps to neutralise excess acid in the blood.The kidneys help to maintain the body's acid-base balance by controlling blood levels of bicarbonate and other acids.
While some parts of the body are naturally acidic in order to aid digestion, the rest of the body requires a slightly alkaline pH in order to support normal cellular function. When the pH of the body becomes too acidic or alkaline, it can lead to a number of health issues including metabolic acidosis or alkalosis, which can be fatal if not treated.

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natashieh t1_j9gn9z4 wrote

Proteins are the functional molecules of the body, but I would not conflate the term amino acid with the generic idea of an acid. An amino acid has three groups: a basic amine group, an acidic carboxylic acid group, and then a functional ‘R’ group that has variable acidity. The concept of pKa is important here; the ionizable (or ability to lose/gain a proton) groups of proteins are based on pH, and this in turn confers a proteins function and interaction with other molecules.

We run slightly alkaline because gas exchange (O2 to CO2) is a tightly regulated process to ensure proper cellular function. Dissolved CO2 is acidic, and our blood (and the organs bathed in blood) needs to stay slightly basic to avoid CO2 build up.

It’s also important to note there are proton gradients in our cells, and these proton gradients drive functions like chemiosmosis (a crucial step in cellular respiration). Organelles like lysosomes are also highly acidic to facilitate breakdown of molecules.

Tldr: amino acids are not acidic just because they have acid in the name, slightly basic blood helps with gas exchange, and you can find membrane-bound structures that are highly acidic within cells.

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NiktonSlyp t1_j9ist9i wrote

There are already answered, so I'll just write cool stuff.

Just like life, it's not black and white or acid and basic. It's just a big mass of chemical equilibrium. Even in a cell, you have different pH for organelles and stuff.

Fun fact : in mitochondria, we use glucose (super complex stuff) to send protons (H+ ions to be simple) in the outer area of the mitochondria. Because the amont of protons is very high in this area (acidic) and lower in the center area (less acidic) while being separated by a membrane, the protons want to go back and they can go through massive barrage that use their force to generate energy. It's called the proton motrice force and it's basically a protein water barrage that generate energy for your cell. Because we spend less energy moving the protons up than they generate by going back, excess energy woohoo. That's breathing baby

Tldr : We didn't invent the principle of water barrages, cells (bacteria) did.

Look up videos of ATP synthase on YouTube, and in the litterature if you want more infos. Super dope stuff.

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