OBJECTIVE LIFE SCIENCE
BIOCHEMISTRY
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
a measure of the catalytic efficiency of the enzyme.
|
|
|
equal to half of Vmax.
|
|
|
the rate constant for the reaction ES
|
|
|
the [S] that half-saturates the enzyme.
|
|
|
a ratio of substrate concentration relative to catalytic power.
|
Detailed explanation-1: -The concentration of substrate required to half saturate the enzyme or in other words to cause half the maximal reaction rate (1/2 Vmax) called as Michaelis Constant or Michaelis-Menten Constant and is denoted by Km.
Detailed explanation-2: -For practical purposes, Km is the concentration of substrate which permits the enzyme to achieve half Vmax. An enzyme with a high Km has a low affinity for its substrate, and requires a greater concentration of substrate to achieve Vmax."
Detailed explanation-3: -As the substrate concentration increases, the enzyme reaction increases until all of the active sites are occupied by the substrate. When all active sites are occupied, the enzyme is saturated. At this saturation point, adding more substrate makes no difference to the reaction rate.
Detailed explanation-4: -Order of reaction: When [S] is much less than Km, the velocity of the reaction is approximately proportional to the substrate concentration (Figure 5.10). The rate of reaction is then said to be first order with respect to substrate. When [S] is much greater than Km, the velocity is constant and equal to Vmax.