객관식
A glycosidic linkage is analogous to which of the following in proteins?
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4. Protein Structure
Peptide Bond
객관식
In the dipeptide shown below, which answer choice correctly identifies the location of the peptide bond? \[ \text{Glycine} - \ce{NH2-CH2-COOH} + \text{Alanine} - \ce{NH2-CH(CH3)-COOH} \] A segment of the resulting dipeptide is: \[ \ce{NH2-CH2-CO-NH-CH(CH3)-COOH} \] Which bond is the peptide bond?
A
The bond between the alpha carbon of glycine and its amino group (\(\ce{CH2-NH2}\))
B
The bond between the carboxyl group of alanine and its alpha carbon (\(\ce{COOH-CH(CH3)}\))
C
The bond between the carbonyl carbon (C=O) of glycine and the nitrogen (N) of alanine (\(\ce{CO-NH}\))
D
The bond between the methyl group of alanine and its alpha carbon (\(\ce{CH3-CH}\))
검증된 단계별 안내1
Step 1: Understand the concept of a peptide bond. A peptide bond is a covalent bond formed between the carboxyl group (-COOH) of one amino acid and the amino group (-NH2) of another amino acid during a condensation reaction, releasing a molecule of water (\(\text{H2O}\)).
Step 2: Analyze the structure of the dipeptide provided. The dipeptide is formed by glycine (\(\text{NH2-CH2-COOH}\)) and alanine (\(\text{NH2-CH(CH3)-COOH}\)). The resulting dipeptide structure is \(\text{NH2-CH2-CO-NH-CH(CH3)-COOH}\).
Step 3: Locate the peptide bond in the dipeptide structure. The peptide bond is the \(\text{CO-NH}\) linkage formed between the carbonyl carbon (C=O) of glycine and the nitrogen (N) of alanine.
Step 4: Eliminate incorrect options. The bond between the alpha carbon of glycine and its amino group (\(\text{CH2-NH2}\)) is not a peptide bond, as it is part of the glycine structure. Similarly, the bond between the carboxyl group of alanine and its alpha carbon (\(\text{COOH-CH(CH3)}\)) and the bond between the methyl group of alanine and its alpha carbon (\(\text{CH3-CH}\)) are structural bonds within alanine and not peptide bonds.
Step 5: Confirm the correct answer. The peptide bond is specifically the bond between the carbonyl carbon (C=O) of glycine and the nitrogen (N) of alanine (\(\text{CO-NH}\)). This is the defining feature of a peptide bond in the dipeptide structure.
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