1. Peptides from sweet potato with antioxidant properties have the following seq

ID: 65479 • Letter: 1

Question

1. Peptides from sweet potato with antioxidant properties have the following sequence of amino acids.

Part A. Draw the structure for Asp-Cys-Gly-Tyr. (Express your answer as a zwitterion.)

Part B. Draw the structure for Asn-Tyr-Asp-Glu-Tyr. (Express your answer as a zwitterion.)

2. Peptides isolated from rapeseed that may lower blood pressure have the following sequence of amino acids.

Part A. Draw the structure for Arg-Ile-Tyr. (Express your answer as a zwitterion.)

Part B. Draw the structure for Val-Trp-Ile-Ser. (Express your answer as a zwitterion.)

The physiological pH here is considered as 7.0; the peptide bonds are written in bold.

1-A-

+NH3-CH(CH2-COO-)-CONH-CH(CH2-SH)-CONH-CH2-CONH-CH(CH2-C6H4-OH)-COO-

1-B-

+NH3-CH(CH2-CONH2)-CONH-CH(CH2-C6H4-OH)-CONH-CH(CH2-COO-)-CONH-CH(CH2-CH2-COO-)-CONH-CH (CH2-C6H4-OH)-COO-

2-A-

+NH3-CH(CH2-CH2-CH2-NH-C(NH2)=NH2+)-CONH-CH(CH(CH3)-CH2-CH3)-CONH-CH(CH2-C6H4-OH)-COO-

2-B-

+NH3-CH(CH(CH3)-CH3)-CONH-CH(CH2-C8H6N)-CONH- CH(CH(CH3)-CH2-CH3)-CONH-CH(CH2-OH)-COO-

(The underlined structure is that of an indole ring).

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