Question

Which of the following synzyme has 27% of the activity of a-chymotrypsin against 4-nitrophenyl esters?

(a) Primary amines alkylated with 1-iodododecane and 4(5)-chloromethylimidazole

(b) Myoglobin achieved by attaching (Ru(NH3)5)^3+ to three surface histidine residues

(c) C-6 hydroxyl group of β-cyclodextrins was covalently derivatized by an activated pyridoxal coenzyme

(d) Polyglutamic acid acts as an esterase in much the same fashion as the acid proteases for the hydrolysis of 4-nitrophenyl acetate

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Answer 1

The correct answer is (a) Primary amines alkylated with 1-iodododecane and 4(5)-chloromethylimidazole

Explanation: Polyethyleneimine is formed by polymerizing ethylenemine to give a highly branched hydrophilic three-dimensional matrix out of which 25% of the resultant amines are primary, 50% secondary and 25% tertiary. If 40% of the primary amines may be alkylated with 1-iodododecane to give hydrophobic binding sites and the remainder is alkylated with 4(5)-chloromethylimidazole to give general acid-base catalytic sites. Thus, the resultant synzyme has 27% of the activity of α-chymotrypsin against 4-nitrophenyl esters and it has very low esterase specificity.