Question 1: Protein and Enzymes (4 parts.) 12 pts. You have a scenario where the

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Question 1: Protein and Enzymes (4 parts.) 12 pts. You have a scenario where there are three proteins that slone are not active. The active assembly consists of two molecules of protein A 2 moleculeS of protein B, and 2 molecules of protein C. How would you describe the quaternary structure of the active assembly? For example, if I felt it was a heterodimer then my answer would be "heterodimer Sickle cell anemia is a disease in which glutamate at position 8 in hemoglobin is mutated to a valine. Based on your understanding of amino acids, which statement below do you think is True? 0 This is a mutation from a negatively charged residue to a neubal polar idue, leading to a subtle change in structure The mutation exposes the valine on the surface where it interacts with water and other neutral polar amino acids, leading to hemoglobin This mutation is conservative in nature and does not lead to much of a change in hemogiobin structure The mutation exposes the valine on the surface, which causes the protein to misfold. As a result multiple mistoided hemoglobin molecules Which staterment about enzymes is false Enzymes accelerate chemical feactions and only t the foaction is thermodynamically favorable Enzymes recognize substrates via active sites, and active sites make up only a small portion of the enzyme Enzymes release the most binding energy via interactions with the transition state Enzymes bind to substrates mainly through non-covalent interacitons All of the above statements are true None of the above statements are true An enzyme bnds a ootactor to catalyze the hydrolysis of a small corpond·Once chemistry is complete both product and cofactor release, egenerating an inactive enzyme. Which statement best deacribes the enzyme It binds to a prosthetic group to become a holoenzyme It binds to a prosthetic group to become an apoenayme It binds to a cosubstrate to become a holoenzyme it binds to a cosubstrate to become an apoenzyme O The above scenario is not possble

Explanation / Answer

1. The answer would be heterotrimer

It is in a way, tetramer of dimers, proteinA would form a dimer, proteinB would form a dimer, protein C would form a dimer and when these three come together to form an active protein, it would be a heterotrimer or heterotrimer of dimers;

2. The answer is option 4: the mutaton exposes valine on the surface which causes the protein to misfold. As a result multiple misfolded hemoglobin molecules aggregate.

The sickle-cell disease occurs when the sixth amino acid, glutamic acid, is replaced by valine to change its structure and function.sickle-cell anaemia also known as E6V that is, glutamic acid (E) on 6th position is replaced by valine (V). Normal red cells maintain a basic disc shape, irrespective if they are transporting oxygen or not. But hemoglobin exists as isolated units in the red cells when they have oxygen bound in Sickle cell diesease. The RBCs with sickle hemoglobin, picks up oxygen at lungs, the hemoglobin molecules resume their solitary existence. The molecules tend to stick together and form long chains or polymers when the oxygen is released in the peripheral tissues and the cell structure is distorted by the rigid hemoglobin. When enough haemoglobin collapses on itself the red blood cells become sickle-shaped. These cresent-like or "sickle shaped" red cells, thus formed, gave the disorder its name.

3. the answer is : all the above statements are true about enzymes.

Initially, the reaction between the active site and the substrate is non-covalent. There are four important kinds of interaction that hold the substrate in a right orientation and form an enzyme-substrate complex- hydrogen bond, Van der Waals force, hydrophobic interaction and electrostatic force.

enzymes are meant to lower the energy of the transition state so as to increase or fasten the reaction rate.

active site is a small part of the enzyme, but it is the important part which helps the binding/recognising the complementary substrate.

4. the answer is option a: it binds to a prosthetic group to become a holoenzyme

An apoenzyme is an inactive enzyme, activation of the enzyme occurs upon binding of an organic or inorganic cofactor

holoenzymes= apoenzyme + avtive site + co factors

Most cofactors are inorganic metal ions.

If a cofactor is an organic molecule, like a vitamin, it's called a coenzyme.

Coenzymes are divided into cosubstrates( bind temporarily)

and prosthetic groups (permanently bound to the enzyme).

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