I'm just posting this because the info I've been finding isn't making sense to me. I'll list my point. (p.s. this is info that I found i'm not making it up so please don't freak out on me because I dont' know something you do)
Point #1. Protein is a chain of amino acids. These amino-acid strings fold back on themselves (the way the strings fold determines the protein's chemical and biological properties). The proteins are held in place by weak bonds (non-covalent) between different parts of the amino-acid string. When you break those strings, by various methods, you are denaturing the protein.
Point #2. Denatured- Denaturing occurs when protein is exposed to high temperatures (typically over 60 degrees Celsius) or to certain chemicals that disrupt the protein structures. After this change the protein can no longer perform its biological function. (Starr and Taggart, 1987.58) This is why you should look for undenatured types of protein.
Okay, if above is true then here's where I get a little confused.
Point #3. The proteins, in its original form, are too large to be absorbed through the intestines. The body breaks them down into smaller components called amino acids. The amino acids are small enough to penetrate the intestinal wall and are absorbed into the blood stream.
Point #4. Steps of Protein Digestion
- reduce particle size to increase surface area
- reduces pH to 2-3
- disrupts hydrogen bonds & DENATURES protein
- secreted by gastric mucosa (chief cells)
- breaks down DENATURED protein
- cleavage of protein at specific AA – aromatic
- breaks peptide bonds
*following steps left out but can include if you want to see them*
Okay, according to Point #3 Proteins are broken down into amino acids and absorbed into the blood stream through the intestinal wall. Intestinal processing takes place after stomach processing, and point #4 states that the HCL in the stomach DENATURES the protein! So what I am getting from this is before you absorb any benefits from the protein it becomes denatured. Therefore leading me to ask... what is the importance of buying non-denatured protein if your stomach is going to denature it before you absorb it anyway?
Thread: Why non-denatured protein?
04-10-2003, 03:34 PM #1
Why non-denatured protein?
04-10-2003, 04:07 PM #2
04-10-2003, 05:28 PM #3
04-10-2003, 06:10 PM #4
04-10-2003, 06:26 PM #5
04-10-2003, 06:49 PM #6
04-10-2003, 06:49 PM #7
Denaturing of proteins isn't always bad. When the albumin in an egg white is denatured by cooking, it turns from a liquid to a solid because some of the hydrogen bonding is being broken down (like said above, but this isn't causing relevant deamination for the bodies utilization). This doesn't make the protein useless, now does it? Unless the cooking was excessive (thus rendering the chains of amino acids destroyed along with the amino acids themselves), the proteins will still be able to be utilized in the body. Then, through digestion (by means of the enzymes pepsin, trypsin, chymotrypsin, and pepsidase, the body breaks down the proteins further into amino acids which are used by the body's cells.Currently bulking...goal 3lbs+ increase every month.
04-10-2003, 06:54 PM #8Originally posted by MushMouth
Hopefully someone who's got some experience in biochemistry will chime in soon, but denaturing of protein doesn't break the bonds, its unfolds the structure. Hydrolysis is what breaks the bond. Or something like that.Currently bulking...goal 3lbs+ increase every month.
04-10-2003, 06:57 PM #9
04-10-2003, 07:15 PM #10
04-10-2003, 07:20 PM #11Originally posted by ManOfSteel2003
Yeah, which will occur inside the body during digestion, not by cooking. What isn't understood here, I'm confused?
Edit (for the 3rd time no less) I see the ambiguity in my post could have been avoided if I'd stated that unfolding breaks the hydrogen bonds, and not the peptide bonds.
Last edited by MushMouth; 04-10-2003 at 07:37 PM.
04-10-2003, 07:36 PM #12Originally posted by MushMouth
He was talking about digestion, and why it was different from denaturing food by heat. When he said that denaturing breaks the bonds, I thought he meant the peptide bonds, and hence my answer that the bonds had to be broken via hydrolysis.Currently bulking...goal 3lbs+ increase every month.
04-10-2003, 08:57 PM #13
04-10-2003, 09:30 PM #14
04-10-2003, 11:01 PM #15
Alright, maybe you guys covered it, but i still don't see the light. Why is it recommended to take non-denatured protein? This is my question. Does your body not absorb protein as well if it is denatured? If you can answer it in laymans terms that would be great. I read the post about the cooked egg and how not all denaturing is bad... so is the topic of denaturing irrelevant? Can you denature protein before consuming and have no loss vs consuming non-denatured protein?
04-10-2003, 11:10 PM #16
Yes, the topic of denaturation of proteins is irrelevant. Unless the proteins were damaged by excessive cooking to the point where the actual chemical structure was broken down, the body has certain proteins that can reorganize and refold the denatured proteins into their correct chemical sequence. Nothing to worry about whatsoever.Currently bulking...goal 3lbs+ increase every month.
04-10-2003, 11:22 PM #17
04-11-2003, 12:23 AM #18
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04-11-2003, 10:00 AM #19Currently bulking...goal 3lbs+ increase every month.
04-11-2003, 10:01 AM #20Originally posted by rapidgrowth
Awesome, thank you for clearing this up ManOfSteel2003. I'm going to call attention to this post when next time I hear someone caution against denatured protein.
P.S. is there a term for when the chemical structure of protein is damaged or broken down by, i.e. excess heat?Currently bulking...goal 3lbs+ increase every month.
04-11-2003, 10:20 AM #21
04-11-2003, 10:55 AM #22
Enyzmes are specific with regard to substrates. Protein conformation is thus important because the active sites for enzymes are specific. If the protein is in a conformation that is "not recognized," it could be shunted into another pathway. Who knows. There are so many pathways, and cerevisiae is obviously different from human.
This lock and key hypothesis is not iron clad, though.
04-11-2003, 11:06 AM #23
PS - What I mean is that denaturing changes a protein's conformation. This could impact its ability to act as the key in the lock, as described in the E+S discussion above. So theoretically, this denaturation could impact its utlimate fate as it cycles through the body's biochemistry. This is one reason why non-denatured protein could be important.
Note that many proteins "spontaneously" refold (i.e., it is thermodynamically favorable for them to resume its original shape). There is also a class of enzymes that I am aware of that participate in protein folding. And the active sites of enzymes are not quite fixed. Because I have no real expertise in human physiology, I can't really say with certainty that non-denatured protein will not be catabolized via Urea Cycle, etc.
The biochemistry can be, to a degree, redundant. We are already aware of the chemistry involved. What makes it so thrilling is the spectacular number of pathways that no doubt meet in the interstices created by certain common enzymes. But all this is only a long way of saying what I should have said at the outset: I'm just guessing.
04-11-2003, 11:39 AM #24
The human body is a spectacular thing, there is no reason to only consume "undenatured" protein sources. If someone is advertising that, then it's just a scheme to fool people into buying their product. No need to look too much into this topic. Just don't overcook your food.Currently bulking...goal 3lbs+ increase every month.
09-22-2016, 11:05 AM #25
09-22-2016, 11:17 AM #26
Technical issue: digestion does not break down protein into aminos, but into aminos and short peptides. Some of those peptides can have biological activity.
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