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Two common α amino acids (2-amino acids) are cysteine and serine - VCE - SSCE Chemistry - Question 4 - 2005 - Paper 1
Question 4
Two common α amino acids (2-amino acids) are cysteine and serine. Their structural formulas are given below. Cysteine: ``` SH | H2N-C-COOH | CH ```... show full transcript
Worked Solution & Example Answer:Two common α amino acids (2-amino acids) are cysteine and serine - VCE - SSCE Chemistry - Question 4 - 2005 - Paper 1
Step 1
i. What chemical feature must an amino acid have in order to be classified as an α amino acid?
Answer
An α amino acid must have both an amino group (–NH2) and a carboxyl group (–COOH) attached to the same carbon atom (the α-carbon). This configuration enables the amino acid to participate actively in peptide bond formation, which is essential for protein synthesis.
Step 2
ii. Cysteine and serine can combine together to form two different dipeptides. Draw the structural formulas of these two dipeptides.
Answer
The two dipeptides formed from cysteine and serine are:
-
Cysteinyl-Serine (Cys-Ser):
H2N-C(Cys)-CO-NH-C(Ser)-COOH -
Serinyl-Cysteine (Ser-Cys):
H2N-C(Ser)-CO-NH-C(Cys)-COOH
Each dipeptide is formed by the condensation reaction between the amino group of one amino acid and the carboxyl group of another, releasing a water molecule.
Step 3
Step 4
ii. Why is the tertiary structure of an enzyme essential to its function?
Answer
The tertiary structure of an enzyme is crucial as it determines the enzyme's active site shape, enabling specific substrate binding. This unique conformation is essential for the enzyme's catalytic activity and overall functionality, influencing the biochemical reactions it can accelerate.