Enzyme characteristic - common feature Flashcards
example of using enzymes for survival
firefly and bombardier beetle
firefly
light
using luciferase
bombardier beetle
use catalase - eject boil acid
example role for enzymes - 6
food digestion (pepsin) blood clotting (thrombin) pressure (ACE defence (lysozyme) breakdown of drugs (cytochrome p450) routine cell process
types of reaction
anabolic
catabolic
interconversion
anabolic
small to large
catabolic
larger to small
interconversion
reaction at equilibrium
enzyme classification
most end in -ase and common name like trypsin
category names
enzyme commission number - 4 digit
category names - how it starts
start with same part being broken down
enzyme commission number
class . subclass . sub-subclass . serial
6 classes
oxidoreductase transferase hydrolase lyase isomerase ligase
oxiderductase
transfer e-
transferase
transfer chemical groups like methyl
hydrolase
break bond with water
lyases
involve double bond
isomerase
transfer of group in molecule
two different substrate modify single molecules
ligase
form bonds using ATP
enzyme necessary - pace of life
2H2O2 -> 2H2O + O2 - H2O2 is dangerous and requires 41 years to remove
therefore using catalase enzyme - 1s to break down
enzyme necessary - condition of life - temp and pH
body temp 37 degrees and 7pH
increase rate - increase temp and pH which destroy cell but enzyme - no high temp needed
rate of reaction depend on
speed of 1 reaction - rate constant
number of reaction happening simultaneously
enzyme in reaction
reduces activation energy
how energy relate to speed - distribution, Ea
uneven distribution of energy
enzyme shifts Ea to left therefore more molecules undergo reaction
each has Ea of 5KJ/mol = 10x faster
enzyme potency
how many times faster with enzyme
e.g. OMP decarboxylase from 78 million yrs to 18ms therefore rate is 10(17)
enzyme properties
reusable - save resources
specific - only desired reaction
efficient - 100% yield of product
controllable - start/stop reaction
active site properties
small part of enzyme
contain binding site and catalytic residue
source of substrate - range of substrate - all have that group therefore enzyme specificity
provide alternative route that requires less energy
lock and key (fischer)
size / shape filter
bind affinity - substrate bind to E
induced fact (koshland)
loose and approximate, bind and changes to correct shape
charge in active site and substrate - attract opposite charge
stereo-specificity
characterise enzymes
Ogston 3-point binding
Ogston 3-point binding
active site has 3 points to have stereospecificity
stereospecificity determined by
3D arrangement of residues
its chemical properties
form catalytic triad
catalytic triade
only 3 a.a carefully positioned in actual catalysis
active site also contains
metal cofactor
coenzyme
prosthetic groups
metal cofactor
small, dense +ve charge
breaks groups like phosphate group using Mg2+ or Zn2+
coenzyme
organic molecule - provide/remove groups
derived by vitamins
act as H shuttle in Redox reaction
no. coenzyme remains same - moving H around
example of coenzyme
NADH -> NAD+ - H transferred to S and leaves as P
prosthetic groups
e.g. Flavin, Haem (catalase)
organic and quite large
post translationally modified protein and also metals as well
