Homogeneous Reaction

8/19/2019 Homogeneous Reaction

1/35

HOMOGENEOUS

REACTION

MK. Rekayasa Biokimia

Smt. Genap 201!201"


2/35

T#e #ea$t o% a typi&a' (iop$o&ess is

t#e $ea&to$ o$ %e$mente$


3/35

Basi& $ea&tion t#eo$y)

Rea&tion t#e$mo*ynami& how far the

reaction can proceed Rea&tion kineti&s t#e rate o% $ea&tions


4/35

Rea&tion t#e$mo*ynami&s

Re+e$si('e $ea&tion

C'ose* system

thermodynamics equilibrium is$eae*


5/35


E,-i'i($i-m &onstant K

/A /B /R /S ... e,-i'i($i-m&on&ent$ations


6/35


T#e +a'-e o% K *epen*s on tempe$at-$e

∆Go$n t#e an3e in stan*a$* %$ee ene$3y

pe$ mo'e

R -ni+e$sa' 3as &onstant

T a(so'-te tempe$at-$e


7/35


stan*a$* &on*ition 1 atm 4 25oC

t#e$mo*ynami& p$ope$ties

6ot#e$ stan*a$* &on*ition %o$ (ioemi&a'

$ea&tions7


8/35

∆Go$n is e,-a' to t#e *i8e$en&e in stan*a$*%$ee ene$3y o% %o$mation (et9eenp$o*-&ts an* $ea&tants



9/35

G is $e'ate* to ent#a'py ent$opy an*a(so'-te T

Eot#e$mi& $ea&tion 6 ne3ati+e7 TK

En*ot#e$mi& $ea&tion ne ati+e T



10/35

:ie'* is t#e amo-nt o% p$o*-&t %o$me* o$a&&-m-'ate*

pe$ amo-nt o% $ea&tant p$o+i*e* o$

&ons-me*

Rea&tion yie'*


11/35

Rea&tion $ate

- T#e $ea&tion $ate &onstant- T#e $ea&tion o$*e$

- E'ementa$y $ea&tion- None'ementa$y $ea&tion


12/35

I$$e+e$si('e $ea&tion)

aA ; bB y : ; z <

RA $ate o% $ea&tion 9it# $espe&t to A

In a &'ose* system)

Rea&tion $ate


13/35

In (iop$o&ess en3inee$in3 t#e$e a$e t#$ee*istin&t 9ays o% ep$essin3 $ea&tion $ate)

Tota' $ate

=o'-met$i& $ate

Rea&tion $ate

6=

&onstant7


14/35

Spe&i>& $ate r A t#e $ate o% &on+e$sion pe$,-antity o% en?yme 6E7 o$ &e''s 6@7 in+o'+e* in t#e$ea&tion

Units o% r A s1 6&e''&ata'yse* $ea&tion7

k3 6-nit en?yme71 s1 6en?yme&ata'yse* $ea&tion7

1 -nit o% en?yme amo-nt o% en?yme 9#i&ata'yses &on+e$sion o% 1 µmo' s-(st$ate pe$

min-te at t#e optima' &on*ition.

Rea&tion $ate


15/35

A'te$nati+e ep$ession %o$ spesi>& $ea&tion$ate)

6+o'-me o% t#e $ea&tion mit-$e

&onstant7

&e'' &on&ent$ation

e en?yme &on&ent$ation

Rea&tion $ate


16/35

T#e $e'ations#ip (et9een $ate o% $ea&tionan* $ea&tant &on&ent$ation an*tempe$at-$e

k $ate &onstant *epen*ent o%tempe$at-$e 6A$$#eni-s7

O$*e$ o% t#e o+e$a'' $ea&tion 6a;(7

Rea&tion kineti&s


17/35

A$$#eni-s e,-ation)

'ot o% t#e 'n k +e$s-s 1!T 3i+es a st$ai3#t'ine 9it# s'ope E!R.

E8e&t o% T on Rea&tion $ate


18/35

E'ementa$y Rea&tion


19/35


20/35


21/35


22/35

T#e Ha'%'i%e

Do$ a >$st o$*e$ $ea&tion t#e #a'%'i%e t1!2 is

&a'&-'ate* as %o''o9s.

Do$ t#e se&on* o$*e$ $ea&tion)

/A at t t /A0

k

693.0t 2/1 =

0

2/1

2/1

o0

]A[k

1 =tor

kt+]A[

1 =

/2]A[

1


23/35

A se-*o>$st O$*e$ Rea&tion Eamp'e #y*$ation o% met#y' io*i*e

CHI6a,7 ; H2O6'7 → CHOH6a,7 ; H;6a,7 ; I6a,7

Rate k /CHI /H2O

Sin&e 9e &a$$y o-t t#e $ea&tion ina,-eo-s so'-tion

/H2O FFFF /CHI ∴ /H2O *oesnt an3e

(y a 'ot


24/35

se-*o>$st O$*e$ 6&ont*7

Sin&e t#e &on&ent$ation o% H2O isessentia''y &onstant

Rate k /CHI /&onstant

k /CHI 9#e$e k k /H2O

T#e $ea&tion is pse-*o >$st o$*e$ sin&e itappea$s to (e >$st o$*e$ (-t it is

a&t-a''y a se&on* o$*e$ p$o&ess.

# *


25/35

T#e Stea*yStateApp$oimation

Eamine t#e %o''o9in3 simp'e $ea&tionmeanism

Rate of product formation, vp,is proportional to the

concentration of an intermediate.

PBA21

1

k k

k →⇔

−

[ ] Bk v Rate p 2==


26/35

#at Is an Inte$me*iateJ

B is an inte$me*iate in t#e a(o+e$e,&tion se,-en&e.

A spe&ies %o$me* in one e'ementa$y stepo% a $ea&tion meanism an* &ons-me*in one o$ mo$e 'ate$ steps.

Inte$me*iates 3ene$a''y sma''

in*ete$minate &on&ent$ations.


27/35

App'yin3 t#e Stea*y State App$oimation6SSA7

ook %o$ t#e inte$me*iate in t#emeanism.

Step 1 B is p$o*-&e*. Re+e$se o% Step 1 B is &ons-me*. Step 2 B is &ons-me*.

[ ][ ] [ ] [ ]Bk Bk Ak

dt

Bd211 −−= −


28/35

T#e SSA 6Cont*7

T#e SSA app'ie* to t#e inte$me*iate B.

[ ]

[ ] [ ] [ ]

[ ] [ ]

21

1

211

k k

Ak B

Bk Bk Ak

0dtBd

+

=

+=∴

=

−

−


29/35

SSA T#e Dina' Step

S-(stit-te t#e ep$ession %o$ t#e&on&ent$ation o% B into t#e $ate 'a9 +p.

[ ][ ]

[ ] [ ]Ak k

k k dtPd

Bk dt

Pd

21

12

2

+=∴

=

−


30/35

SSA Reaction Mechanisms

More examples in sin! t"e stead#$state approximation

on t"e %asis o& t"e &ollo'in! me("anism)

A((ont &or t"e rate la' &or t"e de(omposition o& *2+,

-irst identi t"e intermediates *+ and *+3

2 22,2 g O g NO g O N +→ ][ ,2O N k r =

32,2 NO NOO N ak + →

,232

O N NO NO ak → +

NOO NO NO NO bk

++ → + 2232

2,2 3 NOO N NO ck → +


31/35

1

SSA Reaction Mechanisms

]][[]][[][

,232 O N NOk NO NOk dt

NOd cb −=

]][[]][[][][

3232

,23 NO NOk NO NOk O N k

dt

NOd baa −−=

32,2 NO NOO N ak + →

,232

O N NO NO a

k → +

NOO NO NO NO bk

++ → + 2232

2,2 3 NOO N NO ck → +

]][[]][[][

][,232

,2

,2

O N NOk NO NOk O N k dt

O N d caa −+−=


32/35

SSA - Reaction Mechanisms

A((ordin! to t"e stead#$state approximation set %ot" rates ealto 4ero

0]][[]][[ ,232 =− O N NOk NO NOk cb

][

][

][

][

]][[

2

,23

2

,2

NO

O N

k k

k NO

NO

O N NO

k

k

ba

a

b

c

+==

0][=

dt

NOd 0

][ 3 =dt

NOd

][

bac

ba

k k k

k k NO

+=

][

]][[][

2

,23

NO

O N NO

k

k NO

b

c=

0]][[]][[][ 3232

,2 =−− NO NOk NO NOk O N k baa

][

][

][

][

][

2

,2

2

,2

3

NO

O N

k k

k

NO

O N

k k k

k k

k

k NO

ba

a

bac

ba

b

c

+

=

+

=


33/35


5"e net rate o& ("an!e o& (on(entration o& *2+, is

]][[]][[][][

,232

,2,2 O N NOk NO NOk O N k

dt

O N d caa −+−=

][][

][

][][

][,2

2

,22

,2

,2 O N k k k

k k k

NO

O N

k k

k NOk O N k

dt

O N d

bac

bac

ba

aaa

+−

++−=

][

bac

ba

k k k

k k NO

+=

][

][

][

][

][

2

,2

2

,23 NO

O N

k k

k

NO

O N

k k k

k k

k

k NO

ba

a

bac

ba

b

c

+=

+=

][

][

][,2,2

,2 O N

k k

k k O N

k k

k k k k k k

dt

O N d

ba

ba

ba

aabaaa

+

−

+

+−−=


34/35


%e(ase

6t &ollo's t"at t"e rea(tion rate is

'"ere

][2][

,2,2 O N

k k

k k

dt

O N d

ba

ba

+−=

2][ ,2−=O N υ

][][ ,2,2 O N k O N

k k

k k r

ba

ba =+

=

][ ,2O N k r =

ba

ba

k k

k k k

+=


35/35


1.

2.

.

P C B A ba k k

→ → + ←

ak

]][[][

B Ak dt

P d =

Documents

Homogeneous Reaction