Question

26. The serine 195 sidechain forms acyl-enzyme intermediate following the sessile bond cleavage. To regenerate the serine sidechain, the hydroxide of 27. True or False. Imadazole of His is a strong electrophile for attacking carbonyl carbon atom. nucleophilic attacks the carbonyl carbonyl carbon of the acyl-enzyme intermediate to form tetrahedral intermediate. 28. Write down Michaelis-Menten equation. 29. The following data were obtained in a study of an enzyme known to follow Michaelis-Menten kinetics: Vo (umol/min) Substrate (umol/L) 117 225 324 488 0.8 2 6 1,000 647 The Km for this enzyme is approximately: (show the unit).

Answer 1

26. ans) Serine

27. ans) Imidiazole of His is a good nuceophile which is a base. It will strike the acylating and alkylating compounds by reacting with NH nitrogen. Actually it is not ready for electrophilically attacking the carbon atoms and these substitution reactions maintains the perfect aromaticity.

28. Michaelis-Menten equation is

V₀  = V_max ( [Substrate] / [Substrate] + K_m )

  V₀  = Reaction's Initial Velocity.

V_max = Reaction's Maximal rate.

[Substrate] = Substrate Concentration

K_m  = Michealis Menten Constant.

29. Km value is equal to the substrate concentration, in the meanwhile the velocity is half its maximal value

ans) 4 $\mu$mol/L