[victor]

Hey, when we eat ommelets, we eat denaturated proteine right? can it converted again into amino-acids so those amino-acids can be reconverted again into functional proteine?

[mith]

That’s how digestion works

[Poison]

I remember writing this before but i will write it again for you. When a protein is denaturated, its structure changes. Aminoacids stay the same. The body breaks down proteins into aminoacids and synthesizes its own proteins. I mean, it is broken down even if you eat uncooked protein.

[Dr.Stein]

quote victor:

Hey, when we eat ommelets, we eat denaturated proteine right? can it converted again into amino-acids so those amino-acids can be reconverted again into functional proteine?

Denaturation is an irreversible reaction. It seems like you chop a cloth randomly and angrily. Then finally you realize that you cannot do anything with the cloth anymore. You destroy the structure, the protein chain in this case, though the amino acids are still there, but as a chain it will not functional anymore. It is already broken.
Whereas in digestion, in this case is protein digestion, seems like you cut that cloth properly into patches, so every patch will function as you want them to be, and nothing, or only few things, will not be used. In this case the amin waste that will be excreted out of the body.

[victor]

Ok I got it…only few things broken from that….thanks 😆

[Jelanen]

Denaturation DOES NOT alter or sever the the primary protein structure (amino acid sequence). It does, however, alter the secondary, tertiary and quarternary structure. Digestion on the other hand, breaks a protein into the constituent amino acids. There is a difference, it is a big deal, and we need to get it right and stop confusing people.

From the dictionary on this website:

quote :

denaturation
Reversible or irreversible loss of function in proteins and nucleic acids resulting from loss of higher order secondary, tertiary or quaternary structure) produced by nonphysiological conditions of pH, temperature, salt or organic solvents.

[Dr.Stein]

Did I make people confused with posting a wrong answer? Well, I should blame on my professorto tell me that way then 😆

[jasonkit]

i remember that there is an enzyme digest potein to amino acid
(breaking polypetide bond)

[Poison]

Yes there are. They are called proteases.
PS: Name of that bond is peptide bond.

[b_d_41501]

The wonders of the human digestive system. lol. Yes, this is done through various cycles in the digestion process.

[victor]

That’s why I can said that human is the most complicated machine that world ever have. 😆

[chemistry_freako]

Yea – complications and more complications. great to be part of the ‘human bean’ population =p

[Dr.Stein]

quote victor:

That’s why I can said that human is the most complicated machine that world ever have. 😆

For digestive system, ruminants’ is more complicated than human’s I think… 🙄

[Jokkon]

HCL in our stomach denatures the proteins that we eat too, i think that makes it easier to digest too

my teacher once told us that some denaturation is sometimes reversible, the example that he used was hemoglobin, at pH 7.4 37 celcius, it bonds with oxygen in the lungs, drop o2 off in tissues when pH changes (more acidic forgot what) and 38celcius.

[Dr.Stein]

I don’t think that HCl denaturates our protein. It is needed to activate such proenzyme, it also creates an acidic environment thus enzymes can work properly, also it functions for a desinfectant.

The binding and dropping Hb molecules from HbO2 is not a denaturation process, I think.. The denaturation itself happens when it breaks protein that constructs Hb molecules into peptides or amino acids.

[Jokkon]

yeah, HCL is used to activate pepsinogen, but since the pH in our stomach is so low, it ought to denature at least some of the proteins that we eat wouldn’t it?

[mith]

Hb surrounds the oxygen molecule a la complex ions.

[victor]

Um, wait a minute….I think the condition is like this:
Denaturation = high temperature and high pH (alcalic).
Renaturation = low temperature and low pH (acidic).

I took it from nucleic-acid denaturation and renaturation…I think that it can be analogized with this.

[Jokkon]

?
i think proteins don’t denature in low temperature, just that there is less kinetic NRG, therefore reactions occur slower

[xand_3r]

Jelanen and Poison are right: denaturation doesn’t mean breaking a protein into aminoacids but altering its structure. The primary structure referes to the succession, number and nature of aminoacids while the secondary structure is determined by the intramolecular hydrogen bonds between the oxygen atom of the –C=O group and the H of the amino group ( -NH-) (the secondary structure may be a helicoidal one, resembling to that of the DNA, or a multi-layered one, when the protein is folded). The denaturation process consists in breaking the intramolecular H bonds thus altering the secondary and tertiary structure of the protein and changing their aspect and properties. For example, in our body when a protein (eg an enzyme) is denaturated it is inactive. When a protein is renaturated (the oposite of denaturation) it becomes active.
Denaturation may be reversible or irreversible. For example, reversible denaturation happens when we freeze meat or other aliments (which explains why they don’t alter) or when our hair is wet it curls because of the changings in keratin structure. When the temperature rises or when the hair is dry, the protein regains its old structure. When we are boiling an egg, the albumins irreversibly change their structure, thus modifying their colour (they become white from transparent) and state of agregation (solid from liquid). The denaturation and renaturation of proteins don’t occur in the same conditions like those of the DNA – they can take place at normal, freezing or boiling temperatures, under the action of gamma rays or chemical agents.

[Author]

Posts