Qualification > Sciences

Chemistry ppr 4 doubt

<< < (2/3) > >>

nid404:
Analysis of a polypeptide A showed that the amino-(N-)terminal end is methionine (met)
and that the carboxyl-(C-)terminal end is lysine (lys).
Enzymic hydrolysis of the polypeptide produced the following tripeptides, with the amino
acid residue on the left having the free amino group.
met-ala-gly gly-arg-val ala-gly-arg arg-val-lys ala-gly-ala gly-ala-gly
Work out the sequence of amino acids in A, using the 3-letter abbreviations. Use each
tripeptide once only.

You can have any sequence for this. Use all 6  tripeptides and 8 residues.

The mark scheme says met-ala-gly-ala-gly-arg-val-lys

You can have

met-gly-val-ala-ala-arg-gly-lys  and the like.

nid404:
Give two examples of how interchanging the positions of two amino acids could affect the bonding in, and hence the overall structure of, the protein.


Interchanging the position of amino acids will mean altering the primary structure of the protein. This will in turn have an effect on the bonding in tertiary & secondary structure of the protein. The disulphide bridges may get disrupted because of a change in R group (side chain) The ionic bonding and hydrophobic interactions may get altered.

moon:
I did not understand the tripeptide question but anyways....Thank you very much for ur help. :)

nid404:
I missed the b

So basically the n terminal is met and C terminal(terminal end) is lys. So the chain begins with met and ends with lys. What do you not understand exactly? :\

moon:
why is the aminoacid  -ala - repeated twice and not  -gly-?

Navigation

[0] Message Index

[#] Next page

[*] Previous page