Why is the answer B? It was also noticed that a coenzyme molecule containing a h

Question

Why is the answer B? It was also noticed that a coenzyme molecule containing a hydroxylOH) group binds to the mutated protein in approximately the same location as the original serine but does not alter the structure of the protein in any way. Based on your knowledge of amino acids, enzymes, and catalysis, which of the following is a REASONABLE conclusion? a. b. c. d. The mutant protein cleaves on the carboxy side of phenylalanine. The mutant protein cleaves peptide bonds on the carboxy side of glutamate or aspartate The mutant protein cleaves peptide bonds on the carboxy side of lysine or arginine. The mutant protein functions identical to chymotrypsin.

Explanation / Answer

Mutation is the source of creating new things. A mutant protein is thus a changed protein or altered rotein.

A recent discovery has suggested that a gene mutation results in several amino acid substitutions within an active site.The following substitutions have been identified and are each expected to properly fold and form the active site:

Noramal protein amino acid                      substitution

Valine                                                        lysine

Leucine                                                     Arginine

Valine                                                        Arginine

Serine                                                    Delted and replaced with an coenzyme capable of covalent binding

Histidine                                                   Histidine( no mutation occurs)

Asparatame                                               glutamate

based on above table we come to know , with serine can be deleted and replaced with an coenzyme which is capble of covalent binding and histidine does not show mutation.

As said in question a coenzyme molecule containing a hydroxyl group bonds to mutuated protein in same location as serine but does not alter the structure of protein any way, it is beacuse serine is having ability to get delete and replaced.

The enzyme trypsin cuts the peptide chain from the C-terminal side of basic amino acid and

the enzyme pepsin cuts from the N - terminal side Leucine, asparatic acid and glutonic acid

enzyme chymotrypsin cuts or cleaves the c -terminal of the amino acid having aromatic side chain like phenyalanine, tyrosine and trptophan.

As serine is not aromatic , so enzyme chymotrypsin does not work.

The mutant protein also cannot be like trypsin , which cleaves carboxyl side of lysine or arginine.

Thus the mutant protein functions like Pepsin which cleaves the acidic amino acid lke asparatame and glutamate.

The serine is having - CH2OH group which gets replaced with CH2COOH to form Asparatic acid or CH2CH2COOH to form glutonic acid with out altering any structure of original protein.

serine    = CH2OH- CHNH2- COOH

Asparatame = COOH CH2 - CHNH2- COOH

Glutamate = COOH-CH2-CH2-CHNH2-COOH

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