the biochemGazettE: Proteins Ni!


Reflection on Proteins

Well well, proteins not new but still good topic, twas educational especially the vids. So proteins play a very important roles in our bodies, such as Structural, Transportation, Receptors, Storage, Hormones , Antibodies and enzymes.


So the first  primary structure is just the linear sequence of aa bonded together by peptide bonds.

Secondary is primaly peptide and hydrogen bonding there are two form alpha helix and beta pleated sheet

the alpha helix is not so unknown to us, u see it everyday and wash it frequently…I hope…lol

HAIR and our Nails!


nails 1

 Both of these are both made of the protein Keratin which is a alpha helix. In the alpha  the amino acids link together to form the coil and there are approximately 3.6 amino acids per turn of the helix (coil), bonding occurs between the oxygen of the carbonyl group and the hydrogen of amino group on the 4th aa. These are fibrous protein playing structural roles. Keratin is also a fibrous protein.

Hair tip: Our hair doesn’t only have hydrogen bonding but also disulphide, sugar and salt bridges. Healthy hair tips girls and boys, we must keep a clean and healthy scalp and also eat and exercise properly to even our follicles good. A word to the wise as much as I love that girls hair over processing and dying hair can lead to early hair loss and thinning so kids lets try and do these things not so much. 😀

The beta pleated sheet can be found in our clothing. SILK!

Silk-Satin-Fabric-Plain-Crepe-Satin-Nature-White-          beta-pleated-parallel-anti-parallel

Tertiary structure, now this is where things get interesting this is the 3D structure given to the polypeptide chain, which is held together  by hydrogen bonds, electrostatic bonds, if present disulphide and hydrophobic interactions. Enzyme possess tertiary structure which is very important to them in term of catalytic activity. They are also globular.

images (1)

Quaternary structure possess all the bonding present in tertiary structure but has more than one polypeptide chain present as seen in haemoglobin that functions in a transport form as it carries oxygen to the body’s cells.



Proteins can be denatured but it occurs differently in each level. Denaturation is the disruption of the bonding in the tertiary and secondary structures. Denatutration can occur through extreme heat and pH. Afinesen experiment he tested it on Ribonuclease A and showed that when present in urea and 2mercaploethanol to break the disulphide bridges present. He found that unfolding of the protein only occurred when in these substances and that it re-folded when not in it. Dialysis removed the solution from the protein, this show that once the primary structure is kept intact a protein can always refold.


That was a long, but now I’ll remember some stuff!


Wikipedia. org. “Protein Structure”.

Informaticsindianna. “Afinsen eperiment” “Protein Function”

~Song of the Day~


the biochemGazettE: Amino acid and Protein MCQ!


Which of these are essential amino acids and belong to the Positively charged polar R-groups






vi) Lysine

(a) i only

(b) iii, iv and v

(c) ii, iv and vi

(d) all

2. The triple helix of collagen has many repeating units of Glycine why is that?

(a) Glycine only has a single Hydrogen atom as a side group making it fit perfectly in the small space in the interior of the chain.

(b) Glycine has optimal hydrogen bonding making it easy to be used in the triple helix.

(c)Glycine shows sterioisomerism.

(d) Glycine can bend into the small spacing in the triple helix easily.

Song of the Day:

Perfume- Nee~

Enjoy……p.s this song will annoyingly stick in ur head! HAHA!

the biochemGazettE: A-M-I-N-O ACiDs


Amino acids are very important to us humans particularly because they compose proteins which are very very essential…. 😉 to us. The R-groups/ sidechains can be in various forms such as:

  • Non-polar, aliphatic
  • Polar, uncharged
  • Aromatic
  • Positively charged
  • Negatively charged


In 1806, French chemists Louis-Nicolas Vauquelin and Pierre Jean Robiquet isolated a compound in asparagus that was subsequently named asparagine, the first amino acid to be discovered. Proteins were found to yield amino acids after enzymatic digestion or acid hydrolysis. In 1902, Emil Fischer and Franz Hofmeister proposed that proteins are the result of the formation of bonds between the amino group of one amino acid with the carboxyl group of another, in a linear structure which Fischer termed peptide.”


Essential Amino acids…..what does it mean…basically we can not make these a.a and thus we get it from foods …so lets try to eat good and stay way from d KFC…Thus conversely non-essentials does NOT mean we don not need them but we just make em ourselves. We all know  there are 20 amino acids we all need but only 10 be essential and the other non-essential.

How do amino acids bond??????????


By way of a CONDENSATION REACTION (loss of a small molecule in this case good ole H2O).  The bond formed is a PEPTIDE BOND   a covalent bond between the amino and carboxyl group of 2 amino acids. Polypeptide is a chain of many a.a. it’s a macromolecule.


Well amino acids form protein and well there are levels of structure they are the primary, secondary, tertiary and Quaternary

Primary-linear combination of aa sequence, only posses peptide bonds

Secondary-hydrogen bonds=alpha helix( h-bonding between the oxygen in the carbonyl group to the hydrogen of the amino group on the 4th aa away) and beta pleated (anti-parallel or parallel)

Tertiary- Hydrophobic interatctions and also H-bonds, salt bridges, electrostatic bonds

Quaternary- More than one a.a chains posses all bonding


Basically it was as it always making me uneasy and nervous as heck! But with all dat still learned something,although it was in the vid in quiz atmosphere I go blank

Why are Gly and Pro destabilize the alpha helix?

Gly is the smallest, and because of the single hydrogen being it side chain it has high CONFORMATIONAL FLEXIBILTY.

Proline, has a rigid ring system, thus rotation about the N-C bond is restricted thus introducing a kink .

Why is the alpha helix more predominant in nature?

This is because there is optimal amount of H-bonding within the helix, meaning every single peptide bond is involved in H-bonding except the ones on the ends.


Song of the day: AAA-Party It UP~