2nd Flashcards
The ratio of the amount of a protein present in a sample, which is used as a measure of purification, is known as
specific activity
If a reaction occurs in the absence of inhibitor with rate ν0 and in the presence of inhibitor with rate νi, the degree of inhibition is defined
as
(ν0 - νi)/ν0
The rate equation in competitive inhibition based on Michaelis Menten equation is given by
rmaxS/(Km(1+I/Ki) +S))
Classical noncompetitive inhibition is obtained
only under
rapid equilibrium conditions
In the steady state the material balance equation for any component of a system is
rate of addition - rate of removal + rate of
formation = 0
Predominantly uncompetitive inhibition may be called when
competitive inhibition is greater than
uncompetitive inhibition
The rate equation in non-competitive inhibition
based on Michaelis Menten equation is given
by
rmaxS/ (Km + S) (1+I/Ki)
Which of the following statement(s) regarding
enzymes, is/are false?
Enzymes provide activation energy for
reactions
The slope of Lineweaver Burk plot for
Michaelis Menten equation is
Km/Vmax
The initial velocity, V0, of an enzyme catalyzed
reaction reaches Vmax as
1/[S] → 0
The usual method(s) to solve rate equation of simple enzyme kinetics is/are
Michaelis Menten approach
Briggs-Haldane approach
Numerical solution approach
Michaelis Menten equation can also be written
as
(-Cs)/r = (Cs/rmax)+(Km/rmax)
1/r = (1/rmax)+(Km/(rmax.Cs))
r = rmax-(Km.r/Cs)
Which of the following step is assumed to be the slowest step in the Michaelis Menten equation?
a. The substrate consuming step
**b. The product releasing step **
c. Formation of enzyme substrate complex
When substrate [S] = KM (Michaelis-Menten constant), the velocity of an enzyme catalyzed reaction is about
0.5 * Vmax
A classical noncompetitive inhibitor has
no effect on substrate binding and vice
versa
The active site of an enzyme differs from an antibody-antigen binding site in that the enzyme active site
catalyzes a chemical reaction
Enzymes are basically
Proteins
Which of the following refers to pseudo steady
state?
d(CES)/dt = 0
Most enzymes work by
decreasing energy of activation
Which category of enzymes belongs to class 5 in the international classification?
Isomerases
Lock and key theory is based on the
compatibility of
enzyme and substrate
When an enzyme is functioning at Vmax, the rate of the reaction is limited by
the rate at which the enzyme can convert
substrate to product
The equation for the rate of product formation for simple enzyme reaction is given by (Where
rmax, maximum reaction rate, Cs substrate concentration, Cp product concentration ES, CES enzyme-substrate concentration)
rp = rmax Cs/(Km+Cs)
When [S] = 0.1 *KM, the velocity of an enzyme catalyzed reaction is about:
0.1 * Vmax
β-amylase is
exoenzyme
saccharifying enzyme
Juice clarification extraction is facilitated by
using
Cellulases
Lysozyme is naturally present in
a. egg white
b. bacteria
c. tears & milk
d. all of these
Enzymes act as antimicrobials
- by depriving an organism of a necessary
metabolite - by generating a substances toxic to the
organism - by attracting a cell wall componen
Trichoderma β-glucanase is reported
to stabilize mashing
The bitter taste of the high protein mategrials is
reduced by using
Protease
Sulphydryl oxidase is used for
UHT milk off flavor removal
α-amylase is an endo enzyme which require
Ca
Liquefaction of starch to dextrin is carried out
by
α-amylase
Which is true about rennet?
- It is a mixture of protease chymosin and pepsin
- it is a mixture of rennin and pepsin
Milk digestibility is improved by using
Lactase
Which of the following mainly serve to convert starch into high fructose corn syrup (HFCS)?
α-amylase
Gluco-isomerase
Gluco-amylase
Lysozyme
catalyses hydrolysis of β-1-4 linkages between N-acetyl muranic acid and N-acetyl glucosamine in peptideoglycan
Hersperidinase is used for
juice clarification
Which of the following metallic ion is there in
ascorbic acid oxidase?
Cu
Which of the enzyme combination is commercially used for the removal of oxygen?
Glucose oxidase-catalase
The enzyme used to reduce bitterness of grapes
commonly contains
α-L-rhamonosidase
β-d-glucosidase
Citrus juice debittering can be carried out using
Limoninase
Which of the following enzyme is responsible for causing vitamin B deficiency disease beriberi?
Thiaminase
Soya off flavour removal may be achieved
using
aldehyde oxidase
The reduction in off flavour of beer is practiced
through
diacetyl reductase
Discoloration can be achieved by using
anthocyanase
The prosthetic group present in phenolase
enzyme is
Cu
Enzymes degrade, alter or synthesize a food
component through
oxidation/reduction/isomerization
hydrolysis/synthesis
group transfer
The enzyme β-galactosidase is also known as
isomerase
Chymosin hydrolyses the bond between
Phenyl alanine and methionine
