New lysine chromogenic substrates for trypsin

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Somorin, O.
Okiei, W.O.
Emokpae, T.
Ogunlesi, M.
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Eight new direct chromogenic lysine substrates, namely N~-benzyloxycarbonyl-L-lysine 3,5-dinitroanilide hydrochloride (L-ZLDA'HCI), N~-benzyloxycarbonyl-L-lysine 3-nitroanilide hydrochloride (L-ZLNA'HCI), N~benzyloxycarbonyl-L-lysine 3-nitro-5-bromoanilide hydrochloride (L-ZLNBA'HCI), N ~- benzyloxycarbonyl-L-lysine 3-nitro-5-chloroanilide hydrochloride (L-ZLNCA" HCI), N~-benzyloxycarbonyl-L - lysine 3-nitro-5-fluoroanilide hydrochloride (L-Z LN F A" H C I), N~-benzylo xycarbonyl-L-lysine 3-nitro-5- iodoanilide hydrochloride (L-Z LN I A " H C I), N~-benzylo xycarbonyl-L-lysine 3-nitro-5-(methylsulphonyl) anilide hydrochloride (L-ZLNMA'HCI) and N~-benzyloxycarbonyl-L-lysine 3-nitro-5-(trifluoromethyl) anilide hydrochloride (L-Z LN T A'HCI) were synthesized by the direct condensation of N~-benzyloxycarbonyl, N~-t butyloxycarbonyl-L-lysine and 3-nitro-5X-substituted aniline, where (X=F, Cl, Br, I, H, NO2, CF3 or S02CHa), using dicyclohexylcarbodiimide (DCC) as a coupling reagent. The resulting product, N ~- benzyloxycarbonyl-N~-t-butyloxycarbonyl-L-lysine-3-nitro-5X-substituted anilide was treated with 2 M HCI in dioxane at room temperature to give N~-benzyloxycarbonyl-L-lysine 3-nitro-5X-substituted were found to be stable to relatively wide variations of temperature and pH. Trypsin-catalysed hydrolysis of these substrates at 37°C proceeded at significantly different rates in the following order: L-ZLNIA'HCI> L-ZLNBA'HCI> L￾ZLNCA'HCI> L-ZLNA'HCI> L-ZLNTA'HCI> L-ZLNFA.HCl> L-ZLNMA'HCI> L-ZLDA'HCI. Kinetic and thermodynamic parameters such as K,,, V,,,,=, k,~, E,, AH and AS were determined for the trypsin￾catalysed hydrolysis of each substrate. A Hammett plot of the catalytic rate constants gave a straight line with a p value of - 1.79 at 37°C thus indicating that electron withdrawing substituents inhibit the trypsin-catalysed hydrolysis of the new lysine substrates.
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Research Subject Categories::NATURAL SCIENCES::Chemistry , Trypsin , chromogenic lysine substrates , hydrolysis , catalytic rate constants
Somorin, O., Okiei, W., Emokpae, T., & Ogunlesi, M. (1987). New lysine chromogenic substrates for trypsin. International Journal of Biological Macromolecules,Vol.9(1), 27-31p.