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підручники. біохімія / Uchebnik_po_Biokhimii_E_S_Severin

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NH2

0

 

0

0

0

Ni:N

II

 

II

II

f"'

I I

-o-P-O-P-O-P-oiH{

I

 

I

I

H

H N

~

o-

 

o-

0-

 

 

N

'

 

/

 

H

H

 

',,//

 

 

 

 

 

 

Mg2+

 

OH

OH

 

CxeMa

CxeMaTWIHO po11h K0<paKTopa rrp:u B3a:uMo)l,e:U- CTB:U:U <t>epMeHTa :u Cy6cT])aTa MO)f(IfO npe)l,CTaBHTh KaK KOMIIJieKc E-S-Me, r)l,e E - <t>epMeHT, S - cy6CT])aT, Me - :uoH MeTaJTJia.

B KaqecTBe rrp:uMepa MO)KHO rrp:ueecT:u pacrro11o:x<:eH:ue cy6CT])aTOB B aKTHBHOM ueHT])e reKCOKHHa3hl (p:UC. 2-3).

f eKCOKHHa3a KaTaJI:U3:upyeT rrepeHOC KOHUeBOro, y-<t>oc<t>arnoro ocTaTKa MOJieKYJihI AT<l> Ha rmoK03Y c o6paJoBaH:ueM fJIIOK03o-6-<t>oc<t>arn:

CH2-0H

 

CH2-0-P03H2

H~oH

 

reKcoK111Haaa H~H

 

OH

H

+ AT¢

~H

H

+ A,Q4>

HO

OH

 

HO

OH

 

H

OH

 

H

OH

 

r moKoaa

 

rmoKoao-6-cj:JocQJaT

rmoK03a

r111,QparnpoBaHHblM IAOH MarHIAfl

PMc. 2-3. Yt.t&CTMe MOHOB MarHMtl B npMcoeAMHeHMM cy6cTpaT8 a aKTMBHOM ~HTpe reKCOKMHB3bl. B aKT1tBHOM 1..1eHTpe reKcoK11Haab1 ecTb y'iaCTKltCBfl3blBaHIAfl AJlfl MOneKYnbl rmOK03bl IA KOMnneKca Mg2•-AT<l>. B peaynbTaTe cjlepMeHTaTIABHO~ peaKL.11111 npo111cXOJ:11AT nepeHOC KOHL1eeoro, y-cjloccflaTHOro OCTaTKa MoneKYnbl AT<l> Ha rn10K03y c 06paaoeaH1AeM rnlOK000-6-<f>occpara.

11oH Mg2+ yqacTByeT B rrp:ucoe)l,:uHeH:u:u :u «rrpa- B:uJihHOM» op:ueHrnu:u:u MOJieKYJihI AT<l> B aKT:uBHOM ueHT])e <t>epMema, oc11a6mrn: <t>oc<t>o3<t>:upHy10 CBH3h H 0611erqaH rrepeHOC <t>oc<t>arn Ha fJIIOK03y.

HoHbl MeTaJIJia - cTa6HJIH3aropw aKTHBnoro u;eHTpa «l>epMema

B HeKOTOphIX c11yqaHx :uoHhl MeTaJIJia CJIY:x<:aT «MOCT:UKOM» Me)l()J;y <t>epMeHTOM H cy6cTpaTOM. OH:u BhIIIOJIHHIOT <l>YHKU:UIO cTa6HJI:u3aTOpoe aK- T:UBHoro ueHT])a, 0611erqaH rrp:ucoe)l,:uHeH:ue K HeMY cy6cTpaTa :u rrpOTeKaHHe X:UM:uqecKOM peaKQHH. B pH)l,e c11yqaee HOH MeTaJIJia Mo:x<:eT crroco6cTBoBaTh rrp:ucoe)l,:uHeHmo Ko<t>epMeHTa. I1epeq:uc11eHHh1e Bhlllle <l>YHKU:U:U BhIIIOJIHHIOT TaK:Ue MeTaJIJlhl, KaK Mg2+, Mn2+, Zn2+, Co2+, Mo2+. B OTCYTCTB:Ue MeTaJIJia 3T:U <t>epMeHThl aKTHBHOCThIO He 0611a)J;a10T. TaK:ue <t>epMeHThI rroJiyqrum HaJBaHHe «MeTaJIJI03H3HMhI». CxeMaTwrno )l,aHHhIM rrpou,ecc B3aHMO)l,ettCTBHH <t>epMeHTa, cy6cTpaTa :u MeTaJIJia MO:x<:HO rrpe)l,CTaBHTh CJie)l,YIQIU:UM o6pa30M:

E-Me-S

K MeTaJIJI03H3HMaM OTHOCHT, Harrp:uMep, <t>epMeHT rr:upyeaT KHHa3y (p:uc. 2-4), KaTaJIH3:UpyIOIUHH peaK.UHIO:

0

 

0

II

 

 

II

c-o-

+NICI>

 

c-o- +AT¢

 

1

Pol·

1

C-0 -

 

C=O

II

 

 

I

CH2

 

 

CH3

Cl>occj:JoeHonn111pyeaT

 

n111pyeaT

2. POAb Mem411.1106 B cma6UAwaquu mpemu11noii u 11emsepmu11noii cmpyKmypbl tjJepMenma

110HhI MeTaJIJIOB o6ecrreqHBaIOT coxpaHett:ue BTOplfqttott, TpeTH'IHOH,qeTBepTWIHOM CT])YKTYPhI MOJieKYJihl <t>epMeHTa. TaKHe <t>epMeHThI B OTCyTCTBHe

84

<l>oc¢oeH011m1pyeaT

i.10H MarHll!s:I

YYacToK ces:1Jb1eaH111s:1

AA<I>

PMC. 2-4. Y'l&CTMeMOHOB M&fHMll B npMCoe,qMHeHMM cy6cTpaTa B &KTMBHOM 4eHTpe nMpyeaTKMH83bl. AKTMBHblM 1..19HTP n11pyBaTKMHa3bl MMeeT y4aCTKM CBff3blBaHMff Aflff cjloc:QJoeHonn11pysaTa"" AJ:l<l>. Mg2•y4acTByeT B CTa611n113a41111 aKTMBHOro 1..19HTpa, 4TO o6ner4aeT np11coei:111HeH11e cjloccjloeHonn11pysaTa. B xoi:1e cpepMeHTaTMBHoi1 peaK41111 06pa3yeTcff n11pysaT"" AT<l>.

MOHOB Me'TarrJIOB crroco6Hhl K XHMWieCKOMY KaTa-

Jil13Y, o.ri:ttaKo OHM ttecTa6MJihHhI. Hx mcrttBHOCTh

CHIDKaeTCH 11 AIDKe rroJIHOCThIO ncqe3aer rrptt tte6oJih-

nrnx H3MeHeHHHX pH, TeMrrepazypbI 11 .ri:pyrMX He-

3Ha'IlITeJihHhIXtt3MeHeHHHX BHelllHero OKP)')K:eHHH.

TaKMM o6pa3oM, ttOHhI MerarrJIOB BhIIIOJIIDIIOT cPYH-

KI.IJ110 CTa6ttJIH3aTOpOB OIITMMaJibHOM KOHcPOPMamm

6eJIKOBOM MOJieKYJihI.

Httor.ri:a B cTa6MJIH3aUtttt BToptt'IHOtt11 TpeTnq-

HOtt CTPYKTYPhI rrpMHHMaIOT yqacTtte HOHhl me-

Jl0lJ:H0-3eMeJihHhIX MeTaJIJIOB. TaK, AJIH rroA.!l;ep)l(a-

HHH TpeTH'IHOM KOHcPOPMaUHH rrttpyBaTKHHa3bI Heo6xo.ri:ttMhI ttOHhI K +.

/:(AA cTa6ttJitt3aUHM lJ:eTBepT11qttoi1 CTPYKTYPhI

aJIKOfOJlb)J;erH)J;poreHa3hI, KaTaJIH3HPyIOIUett peaK-

UHIO OKHCJieHHH 3TaHOJia, He06XO)J;HMhI HOHhl UMH-

Ka. MKOfOJlhAem.ri:poreHa3a COCTOHT 113 4 cy6'heAHHHU c MOJieKYAAPHOH MaCCOH 151 I<):(. B COCTaB cllepMeHTa BXO.!l;HT 4 aTOMa Zn2+. Y.ri:aJieHHe Zn2+

rrpttBOAHT K IlOTepe aKTHBHOCTH cllepMeHTa 3a C'IeT AHCCOUHaUMH Ha 4 HeaKTHBHhie cy6ne)J;HHMUhI c MOJieKYJIHPHOM MaCCOH 36 I<):( (pttc. 2-5).

3. POAb Mema.tl.!lOB 6 rjJepMenmamu6HOM

Kamt1J1U3e

He Mettee BIDKHYJO poJlh OTBOAHT ttoHaM MeraJI-

JIOB B ocyiuecTBJieHHH cllepMeHTaTHBHOfO KaTaJIJ13a.

Y'lacTHee 3JieK'fPO!J>HJibHOMKaTaJIH3e

Ha1160Jiee qacTo 3TY Q:>yHKUHIO BhIITOJIHHIOT

HOHhI MeTaJIJIOB c rrepeMeHHOM BaJieHTHOCThIO,

HMe10m11e CB060AHYIO d-op6ttTaJib H BhICzynaIO-

36 K,Q

36 K,Q

 

 

 

Zn2+

 

Zn2+

00

 

 

 

 

 

+ 4Zn2+

 

 

 

 

 

 

 

 

 

 

0036 K,Q 36 K,Q

 

 

 

 

 

 

 

- 4Zn2+

 

Zn2+

151 K,Q

Zn2+

<l>epMeHT He aKTll!BeH

 

 

 

AnKOfOilbAerMAPOreHa3a

 

 

 

<l>epMeHT aKTll!BeH

 

PMc. 2-5. Poni. MOHOB 4MHK8 e cTa6MnM3&4MM 'leTeepTM'IHOMCTPYKTYPbl anKoron1.AerMAporeHaab1.

85

mtte B Kaqecrne 3JieKTpoqmJIOB. 3TO, B nepsyro oqepe,llh, TaKHe MeTaJIJihl, KaK Zn2+' Fe2+' Mn2+' Cu2+. HoHhl meJIO'iH0-3eMeJihHbIXMeTaJIJJOB, TaKHe KaK Na+ 11 K+, He o6Jia,llaIOT 3THM csoH:cTBOM.

B Ka'ieCTBeIIPHMepa MO)l(HO paCCMOTPeTh $yHK1IHOHHPOBam1e <t>epMeHTa Kap6oaHfH,llpa3hl. Kap6oaHrH,llpa3a - U:HHKCO,llep)l(allIHM $epMeHT, KaTaJIH3HPYIOIIIHH peaKIIHIO o6pa30Bamrn yroJihHOH KHCJIOThI:

co2 + Hp ~ H2C03"

Hott Zn2+ B pe3yJihTaTe 3JieKTpo$HJihHOtt aTaKH yqacrnyeT B o6pa3oBaHHH ff+ H OHHOHOB H3 MOJieKYJihl BO,llhI:

H

H

E- Zn2+ + 0

-.=:::!- E - Zn~:~---·6 + H+

/

 

'H

IlpOTOH H fH,llpOKCHJihHasI rpynna IIOCJie,llOBaTeJibHO IIPHCOe,llHIDllOTCH K ,llHOKCH,lly ymepo,lla c o6pa30BaHHeM yronhHOH KHCJIOTbI (CM. cxeMy A).

B XO.Ile 3JieKTpo$HJihHOro KaTaJIH3a HOHbl MeTaJIJJOB qacTo yqaCTBYIOT B CTa6HJIH3au;m1 npoMe- )J()'TO'iHbIXcoe;a:HHeHHH.

YlfaCTHe s OKHCJIHTeJ11tuo-eoccrauoBHTeJILHhlX

peaKUIDIX

HoHbl MeTaJIJJOB c nepeMeHHOtt saneHTHOCThIO

MOryT TaIOKe yqaCTBOBaTb B nepeHoce 3JieKTpOHOB.

HarrpHMep, B llHToxpoMax (reMco;a:ep)l(aIIIHX 6en-

Kax) HOH )l(eJie3a cnoco6ett npttcoe;a:ttIDITb tt oT;a:a- BaTh O,llHH 3JieKTpoH:

-e·

Fe2+ -.=:::!- Fe3+

+e·

Enaro,llapH 3TOMY csottcrny U:MTOxpoMbI yqacTBy-

JOT B OKHCJIHTeJibHO-BOCCTaHOBMTeJibHblX peaKllllSIX. ,Upyro:H npttMep yqacTMH MOHOB MeTaJIJIOB B

OKHCJIMTeJibHO-BOCCTaHOBMTeJihHblX peaKIIHHX - pa6orn <t>epMema ;a:o$aMMHfHJlPOKCHJia3bI, KamJIH3HPYIOIIIero peaKU:MIO o6pa30BaHMH HOpa,llpeHaJIMHa IIPM yqaCTllll BMTaMHHa c (CM. cxeMy 6).

3a OKMCJIHTeJibHO-BOCCTaHOBHTeJibHbie CBOHCTBa y ,llO$aMMHfHJlPOKCHJia3bl orneqaeT HOH Me,llll (puc. 2-6).

<l>epMeHT, co,llep)l(allIHH HOH Cu2+, He sczynaeT B peaKIIHIO c MOJieKYJIOH KllCJIOpO,lla. Ilptt BOCCTaHOBJieHHll Cu2+ ;a:o Cu+ c noMOIIIbIO acKop6HHOBOH KHCJIOTbl o6paJyeTCH HOH Me,llH, cnoco6Hblll B3aHMO,lleHCTBOBaTb c KMCJIOpO,llOM c o6pa30BaHHeM nepeKHcHoro coe,llHHeHHH. Aanee rH,llpoKCHJibHasi: rpynna nepeHOCHTCH Ha MOJieKYJIY .llO$aMHHa c o6pa30BaHtteM HOpa,llpeHaJIHHa.

4. PoJlb MeraJI.JIOB B perym1UHK aKTKBHOCTH

c)>epMeHTOB

Httor,lla HOHbl MeTaJIJJOB Bb1czyna10T B poJitt peryJIHTOPHhlX MOJieKYJI. HanpttMep, HOHbI Ca2+ cny- )l(aT aKTttBaTopaMtt $epMeHTa npoTeHHKHHa3bI C,

H

0 = C =0

-.=:::!-

H

+ H -.:::!-

E- Zn~!___ -6 + H+ +

E- Zn----- 0

 

 

 

2+ • /

+

 

 

 

~ (/,/

 

0

 

O==C==O'

 

 

 

 

2+

II

-.:::!.

E - Zn2+ + H2COa

 

E-Zn-------- 0 - c -OH

 

 

I

 

 

 

CxeMaA

H

 

 

 

 

 

 

 

 

¢t

02

H20

¢tH

 

 

 

 

CH2

H46n0 ~H26n

CH-OH

 

I

AcKop611HoeaR

,Qer111ApoacKop611HoeaR

I

 

CH2

KlllCilOTa

KlllCilOTa

CH2

 

I

 

 

I

 

NH2

 

 

NH2

CxeMa 6

,QocpaMlllH

 

 

HopaApeHan111H

 

 

 

 

86

NAD+, NADP+.

 

O=C~

 

0=<(1

1.

2E-Cu2+ + HO-?H 0 µ

2E-cu+ +

O=C

I 0 +2W

 

HO-<(H I

 

O=yj

 

HC_J

 

HC

 

I

 

I

 

HO-CH

HO-CH

 

I

 

I

 

H2C-OH

 

H2C-OH

 

AcKop611 HOBaR

,Qer11ApoacKop611HoBaR

 

Kl1CJlOTa

 

Kl1CJlOTa

2.

E-Cu+ + 0 2 + H+ µ

E-Cu-0-0-H

3.

HopaApeHa1111H

PMC. 2-6. Yl.faCTMe MOHS M8AM B aKTMBat.1MM Monet<ynbl KMcnopOAa npM rj>yHKl.IMOHMpoeaHMM Aorf>BMMHrMAPOKCMn83bl. 1 - BOCcraHoBneHMe Cu2•, BXOAfll.llero e cocrae aKTMBHOro 1..1eHrpa Ao¢aMMHrMAPOKc1o1naab1, AO Cu• c noMOl.llblO acKop6MHOBOM KMCflOTb1;

2 - B3al1MOABMCTBM8 Cu·c KMCflOPOAOM c o6pa30BaHMBM nepeKMCHOro cOeAMHBHl1fl; 3 - nepeHOC rMAPOKCMflbHOM rpynnbl Ha MOneKYny Ao¢aMMHa c o6paaoeaHMeM Hopai:ipeHanMHa.

KaTaJIH311py10mero peaKU1111 cl>occl>op11JI11posamrn 6eJIKOB (cM. pa3,n;eJI 5). HoHhI Ca2+ TaIOKe 113Mem110T aKTl1BHOCTb p51)1,a Ka.JibU11H-KaJibMOJJ;yJI11H3aBl1- C11MblX cl>epMeHTOB (CM. no.n;pa.3,lleJI V).

6. Ko<t>EPMEHThI

KaK }')Ke6hmo cKa3aHo, wrn npo.SIBJieH11H KaTaJil1TH'IecKoH: aKTl1BHOCTH 60.TiblllHHCTBY cl>epMeHTOB He06XO.Il.11MO Ha.JI11q11e Kocl>epMeHTa. I1CKJIIOqeH11e COCTaBJI.SllOT fl1.Il.POJil1Tl1qecK11e cl>epMeHTbl (Hanpu:Mep, npoTea3bI, JI11na3hI, pu:6oHyKJiea3a), BbinOJimn01u11e CBOIO cPYHKU11IO B OTCYfCTBl1e KOcl>epMeHTa.

Kocl>epMeHT, JIOKa.Jil13Y.SICh B KaTaJI11Tu:qecKoM yqacTKe aKTHBHoro ueHTPa, npu:H11MaeT Henocpe,llcrneHHoe yqaCTl1e B X11Ml1qecKOH peaKUHH, BbICTYna.SI B KaqecTse aKUenTopa H .n;oHopa XHM11qecK11X rpyrrnu:posoK, aTOMOB, 3JieKTpOHOB. Kocl>epMeHT MmKeT 6bITh CB.SI3aH c 6eJIKOB0H qacThIO MOJieKYJlbl KOBa.JieHTHbIM11 H HeKOBa.JieHTHblMl1 CBSI3.SIMl1.

B nepBOM cJiyqae OH Ha.3hIBaeTCSI npocTeTu:qecKotl rpyrrnotl (Hanp11Mep, FAD, FMN, 6110THH, 1mnoeBa.SI KHCJIOTa). BMecTe c TeM 113BeCTHhr np11Mepb1,

Kor.n;a Kocl>epMeHT np11coemmHeTcH K <t>epMeHTY HeKOBa.JieHTHblMl1 CBSI3HMH HaCTOJlhKO npoqHo, qTQ

He ,u:11ccou:u:11pyeT OT 6eJIKOBOH MOJieicyJibI, Hanpu:- Mep THaMllli,llJl.cPOC<t>aT.

Bo BTOPOM CJiyqae Kocl>epMeHT B3al1MO,lleHCTBYeT c cl>epMeHTOM TOJlhKO Ha BpeMH XHM11qecKOH peaKU11H 11 MO)l(eT paccMarpmmThc.SI B Kaqecrne HrO- poro cy6cTpaTa. Tipu:MephI -

Anocl>epMeHT o6ecneqHBaeT crreu11cl>mttocTh .n;etlCTBHH 11 OTseqaeT 3a BbIOOp Tl1fla XHMH:qeCKOfO npeBpameHHSI cy6cTpaTa. 0,1111H 11 TOT )l(e Kocl>epMeHT, B3a11Mo,u:eH:cTBYH c pa3.Jlu:qHhIM11 arro<PepMeHTaM11, MO)l(eT yqacTBOBaTb B pa.3HbIX x11M11qecK11X npespaIUeHHSIX cy6cTpaTa. HarrpttMep, rr11p11.IJ.0KcaJibQ>occl>aT B 3aBHCHMOCTl1 OT Toro, c KaKHM arrocl>epMeHTOM B3aHMO,lleHCTByeT' yqaCTByeT B peaKUH.SIX TpaHcaMHHHpoBaHHSI 11.TIH ,L(eKap60KCHJil1POBaHHSI aMl1HOKHCJIOT.

XttMu:qecKaSI rrp11po,lla Kocl>epMeHTOB, 11x <l>YHKUH11 B cl>epMeHTaTHBHbIX peaKUH.SIX qpe3BbJqatlHO pa3Hoo6pa3HbI. Tpa,JI11u110HH0 K Kocl>epMeHTaM OTHOCSIT rrpOH3BO,L(Hbie Bl1TaMl1HOB, XOTSI IlOMHMO HHX eCTb 3Haq11TeJibHbIH KJiacc He6eJIKOBbIX COe.Il.11HeHl1H, npHHHMaIOIUHX yqacT11e B

87

npOHBJieHHH KaTaJIHTJfqecKOH $yHKU:HH $ep-

I. MexanU3M «nunz-nonz»

 

 

MeHTOB.

CxeMaTHqHo MexaHH3M

«IIHHr-rroHr» MO)[(eT

K Ko$epMeHTaM OTHOCHT cne.JlYIOlll.lle coerorneHHH:

6bITb rrpe,!1,CTaBJieH CJie,ll,YIOII(HM o6pa30M:

 

npOH3BO,ll,Hbie BHTaMHHOB;

 

 

 

 

 

reMbI, BXOMIIIHe B COCTaB U:HTOXpOMOB, KaTa-

P1

B

 

 

 

 

 

 

 

Jia3bI, nepoKCM,Ll,a3bI, ryaHHRaTU:HKna3bI, NO-

E + A -- t EA l

E'l

 

 

 

CHHTa3bI H HB.illllOIIIHeCH npocTe~eCKOH rpyn-

E'B-- t P2 + E

 

 

noH $epMeHTOB;

 

 

 

 

 

 

ttyKneOTH,lJ,bI - ,ll,OHOpbI H amenTOpbl OCTaTKa

Cy6cTpaT A, B3filfM0,!1,eHcTByH c $epMeHTOM (E),

 

$oc$opHOH KHCJIOTbI;

rrpeBpaIIIaeTCH B rrpo,!J,yKT (P,). <l>epMeHT OCTaeTCH B

yfiHXHHOH, HRH KO$epMeHT Q, yqaCTBYIQII(HH

pe3yJibTaTe 3T0f0 rrpeo6pa30BaHHH He B HaTHBHOH

 

B nepeHoce ~meKTpOHOB H npoTOHOB B UIT3;

$opMe, a B H3MeHeHHOH (E')B pe3yJibTaTe MO,ll,H$H-

• $oc$oa,n;eH03HR$oc$ocynh$aT, yqacTBYIQII(HH

Kau:HH Ko$epMema. )],anee K aKTHBHOMY u:eHTpy E'

 

B nepeHoce cynh$aTa;

rrpHcoe,ll,HHHeTCH cy6cTpaT B, rro,!1,BepraIOII(HHCH rrpe-

S-a,n;eH03HnMeTHOHHH (SAM) - ,ll,OHOp Me-

o6pa3oBaHHIO B npO,!J,yKT (P2) c BbICB060)K,Ll.eHHeM

 

THRbHOH rpynnhI;

HaTHBHOH $opMbI $epMeHTa (E).

 

myTaTHOH, yqaCTBYIQIIIHH B OKHCJIHTeJibHO-

XopolllHH rrpHMep MexaHH3Ma «IIHHr-rroHr»

-

 

BOCCTaHOBHTeJibHbIX peamHHX.

pe~ TpaHcaMHHHpoBaHHH c yqacTHeM $epMeH-

CTpoeHHe H $yttKU:HH 3THX Ko$epMeHTOB no,ll,-

TOB aMHHOTpaHc$epa3 (Ko$epMeHT IIHpH,!1,0KCaJib-

po6Ho pacCMOTpeHbl B COOTBeTCTBYIQII(HX pa3,!1,e-

$oc$aT). AMHHOTpaHc$epa3bI, OTKpbITbie OTe-

Jiax yqefiHHKa.

qecTBeHHbIM yqeHbIM AE. IipayttlllTeHHoM, KaTaJIH-

 

 

3HPYIOT o6paTHMbie peamHH rrepeHoca aMHHorpyn-

B. MYJihTHCYBCTPATHhIE PEAKQHH

nhI c aMHHOKHCJIOThI Ha KeTOKHCJIQTY. MexattH3M

«IIHHf-IIOHf» ,ll,aHHOH peamHH cxeMaTJfqHo rrpe,!1,-

 

 

bOJiblllHHCTBO $epMeHTOB KaTaJIH3HpyeT peaK-

CTaBJieH Ha pHC. 2-7.

 

 

 

U:HH, B KOTOPbIX yqacTByeT 6onee qeM 0,!1,HH cy6-

)],pyroii npHMep MexaHH3Ma «IIHHrIIOHf»

-

cTpaT. B cnyqae ecnH KO$epMeHT He HBnHeTCH

peaKU:HH ,ll,erH,!1,pHpoBaHHH c yqacTHeM KO$epMeH-

npocTeTHqecKoH rpynnoH:, ero TaIOKe MO)[(HO pac-

Ta FAD ( $naBHHa,n;eHHH,!1,HttyK.JieoTM) HRH FMN

cMaTpHBaTb KaK eme O,ll,HH cy6cTpaT. Cne,!J,OBa-

($JiaBHHMOHOttyKJieOTM,L1,), KOTOpbie rrpoqHo CBH-

TeJibHO, yqaCTHHKOB $epMeHTaTHBHOH peaKQHH

3aHhl c $epMeHTOM H, CJie,ll,OBaTeJibHO, He MOryT

MO)[(eT 6bITb HeCKOJibKO: Henocpe,!1,CTBeHHO $ep-

paccMaTpHBaTuCH B Kaqecrne BToporo cy6cTpaTa.

MeHT, HeCKOJibKO cy6cTpaTOB H KO$epMeHT.

CxeMaTmHo CTpYKTYPa 3THX Ko$epMeHTOB H co-

B 3THX cnyqanx MexaHH3M $epMeHTaTHBHOH

OTBeTCTBYIQIIIHe HM XHMHqecKHe $OPMYJibl rrpe,!1,-

peaKU:HH, KaK npaBHJIO, MO)[(eT H,ll,TH no 0,!1,HOMY

CTaBJieHbl Ha PHC. 2-8.

 

 

 

H3 ,ll,Byx nYTeH: no MexaHH3MY «nHHr-noHr» (Me-

FMN H FAD yqacTBYIOT B OKHCJIHreJibHO-BOC-

xaHH3MY ,ll,BOHHOfO 3aMell(eHHH) MJIH IIOCJie,ll,O-

crnHoBHTeJibHbIX peaKU:HHX, aKUeIITHPYH 2 e- H

BaTeJibHOMy. PaccMOTPHM o6a MexaHH3Ma.

2 H+ BH30aJIJiaKCa311HOBOMKOJlbUe (cM. cxeMY HH)[(e).

 

0

 

 

H

 

 

II

 

o ."'cYyVNH

+ H3CYyNY'NH

 

HC~NAN~O

 

HC~NAN~O

 

3

I

3

I

I

 

 

 

R

 

 

R

H

 

FAD (FMN)

 

 

FADH2 (FMNH2)

 

OKHCJ10HHaff ct>opMa

 

 

BOCCTaHOBJ10HHaff ct>opMa

88

90).

1j/a-KK,

PMc. 2-7. Co6b1TMH e SKTMBHOM 1..1eHTpe 8MMHOTpaHc<j)epa3bl KSK npMMep MeX8HM3M8 «nMHr-noHr>>. KocpepMeHT m1p111i:ioKcanbcpoccpaT (nCD), CB5l3aHHbli1 c cpepMeHTOM, npVIHVIMaeT a-aMVIHOrpynny OT nepsoi.1 aMVIHOKVICnOTbl (AK,), KOTOpas:i nplll 3TOM npespalljaeTCs:l B a-KeTOKVICnory 1 (KK,) VI BblCB060)l(,QaeTC5l Vl3 aKTVIBHOro l\8HTpa cpepMeHTa. ,Qanee B aKTVIBHbii.1 l\8HTP cpepMeHTa npVIC08AVIH5l8TC5l a-KeTOKVICnorn 2 (KK2), KOTOpas:i 3a6V1paer aMVIHOrpynny OT KocpepMeHTa VI npeapalljaeTCs:l B a-aMVIHOKVICnOTY (AK2).

CxeMy peaKu1111 ).lem).lp11posaH115l (KaK np11Mep MexaHl13Ma «n11Hr-n0Hr» c ylfacT11eM KoQ:>epMeHTOB FMN 11 FAD) MO)l(HO npe).lCTaBHTb B cJleJ.lyJOmeM Btt).le:

B

2. IlocJ1eiJ0Bame.nbHb1ii Mexanll3M

B CJlylfae nocJle).loBaTeJlbHoro MexaHl13Ma ).lJ151 npOTeKaHH51 Q:>epMeHTHOti: peaKUHH Tpe6yeTC51 0).l- HOBpeMeHHO B3aHMO).leHCTBHe LlBYX cy6cTparoB. B 3TOM cJlylfae B03MO)[(HO np11coe).l11HeH11e cy6CTparoB LlBYM51 pa3Jll1lfHb!Ml1 nyrnMH:

MexaHH3M ynopAAO'lettuoroB3aHMo)J,encTBm1 cy6crpaTa c aKTHBHblM 11euTpoM cj>epMeHTa:

me AH 2

-

).lOHop BO).lopo).la, OKHCJlHeMbitt cy6-

CTpaT

1;

A

-

OKl1CJleHHa51

Q:>opMa cy6cTparn

1;

B -

aKuemop BOLlOPOLla -

cy6cTpaT

2;

BH 2

-

BOCCTaHOBJleHH351 Q:>opMa cy6cTparn 2;

E

(FAD),

E (FADH7)

-

OKHCJieHH351

H BOCCTaHOBJleHH351

Q:>opMbI KoQ:>epMeHTa FAD, BXOLlHIUero s cocrns Q:>epMeHTa E.

B KalfecTBe np11Mepa FAD-3as11c11Moti peaKu1111 MO)[(HO np11BeCTl1 CYKUl1H3T).lem).lporeH33HyJO pe3KUHIO. B 3Toti: peaKu1111 B KalfecTBe srnporo cy6CTparn ylfacTByeT y611x11HoH - O).lHH 113 nocpe).l- HHKOB UCT3 (cM. cxeMy Ha c.

CTepBbIM B 3KT11BHb!H UeHTp Q:>epMeHTa np11COelll1H5leTC5l cy6cTpaT A, o6Jierlfa51 np11coe- D:HHeH11e cy6crparn B. CTOCJle XHMl1lfeCKOH MOlll1cPHKaUHH TaK)[(e Ha6Jll01l3IOT orrpe).leJleHHblH nop51).l0K BbICB060)l().leHirn nponyKTOB peaKUH11.

MexattH3M CJiy'laH:uoroB3aHMO)J.eitcTBHH cy6cTPaTa c aKTHBHblM u,euTpOM cj>epMeHTa:

E + A-----

>

EA + B"-.

5- EP2 -

E + P2

 

 

EAB---

+ EP1P2

 

E + B -----

>

EB + A/'

~ EP1 -

E + P1

89

A

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

<1>11ae111H

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(1113oa1111aKca3111Hoeoe

 

 

 

 

 

 

 

 

 

 

 

 

 

KOilbl..10)

 

 

 

 

 

 

 

 

AAeH111H

 

P1116oqmae111H

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(BlllTaMlllH 82)

 

 

 

 

 

 

 

 

® -+

-----

+-®

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

FMN (cp11ae111HMOHOHyKileOT111.Q)

 

 

AM<I> (a.QeH03111HMOHocpoccpaT)

 

 

r-------------------------------------------,

:--------------~----­

 

 

 

 

 

 

 

 

 

:HaCUNXN,

NH

 

 

 

 

 

:

 

I

"

 

 

 

 

 

 

 

 

 

 

 

iH3C~

 

 

N~NAO

 

 

 

 

 

 

 

 

 

 

 

 

 

 

I

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

HC-H

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

I

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

HC-OH

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

I

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

HC-OH

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

I

 

 

:0

 

 

 

 

 

 

 

 

 

 

 

HC-OH 0

 

 

 

 

 

 

 

 

 

 

 

 

 

I

II

 

111

 

 

 

 

 

 

 

 

 

 

 

 

H2C-0-P-0-,P-0- CH2

 

 

 

 

 

 

 

 

 

 

 

 

I

 

11

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

OH

pH

I I I

I

OH OH

--------------------~

PMc. 2-8. CTPYKTYPB (A) MxMMM'4eCKOecTpoeHMe (6) KO(j>epMeHTOB FMN M FAD.

coo-

l

CH

II

CH

too·

<l>yMapaT

Y6111XHHOI1

90

Ilp11op1nerHocr11 3a B3a11MoneitcrB11e cy6crparoB A 11 B B aKT11BHOM u:ettrpe <PepMeHra Her (KIDK,ll,bIH cy6crpar 11Meer CBOH u:eHrp CB.H- 3bIBaHl1.Sl B aKTl1BHOM u:eHrpe). TaIOKe Her crporo:H 3aKOHOMepHOCTl1 BbICB06mK,D,eHH.Sl rrponYKTOB peaKu:1111.

Ilp11MepoM IIOCJie,D,OBareJibHOro yrrop.SlL(O'leHHOro MexaH113Ma MO)l(er 6hITb peaKu:11.11 ner11np11p0Batt11.11 c yqacr11eM Ko<PepMeHTOB NAD+, NADP+.

CxeMaTH'lHOcrpYKTYPa 11 XHMH'lecKHe<l>oPMYJibI 3TI1X KO<l>epMeHTOB rrpe,D,CTaBJieHbl Ha p11c. 2-9.

A

06a KO<l>epMeHTa <l>YHKIJ:110Hl1PyIOT KaK rrocpe,D,- Hl1Kl1 rrepettoca ,D,Byx 3JieKTpOHOB 11 O,D,HOro rrporoHa or ,D,OHopa K aKu:errropy, ,D,pyroro rrporoHa - B cpeny (CM. CXeMY A Ha c. 92).

.ll:ottop u aKu:errrop He 06113areJibHO yqacrnyior B 0,D,HOM Mera60JIH'leCKOMrryr11. LJ:pyr11M11 CJIOBaMU, BOCCTaHoBJieHHa.Sl <PopMa 3TUX HyKJieOTUL(OB ne:Hcrnyer KaK o6mu:H rryJI 3JieKTpottoB, 06pa30BaHHbIH B pe3yJihTare OKl1CJil1TeJibHbIX peaKQUH, " MO)l(eT 6bITb UCIIOJib30BaHa B pa3JIU'lHbIXBOCCTaHOBl1TeJibHblX peaKuu.11x. TaKHe peaKQuu tta3hIBa10r corrp.11)l(eHHhIM11 (cM. cxeMy Ii Ha c. 92).

Hlo1KOn1H8Ml1,D,

(Blo1T8Mlo1H}

~ ®--+--!----®-~

 

 

 

'---~~

 

 

 

 

 

~~~

 

Aono11H1o1Te11bH8ff

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

¢>oc¢>aTHaff

 

 

 

 

 

 

 

 

 

rpynna

 

 

 

 

 

 

 

 

 

y NADP+

 

 

 

 

 

 

AMCI> (a.QeH031-1H-

 

 

 

 

 

 

MOHo¢>oc¢laT)

Ei

 

 

 

 

NH2

 

 

 

 

 

 

 

 

 

NH2

0

 

 

 

N:CN

~

c~

 

 

~

I

I

 

ONH,

00

lN)

 

~N

CH2-0-~-0-~-0-~C2

 

 

 

 

 

 

I

I

0

 

 

 

 

 

H

OH

OH

 

 

O

 

 

 

 

 

 

II

 

HOH

OH

 

 

HOH

OH (-~-OH)

OH

PMc. 2-9. CTPYKTYPB (A) MXMMM~ecKoe cTpoeHMe (6) Ko<ilepMeHTOB NAO+ MNAOp+.

91

retta3a;
E2 -
c. 93),
r.ri:e E, -
E1 11

aC-NH,

0NI

H

//0

 

 

 

 

NI

 

 

 

 

D +

 

 

 

 

 

 

 

 

R

 

 

 

 

 

R

NAO+ (NADP+)

NADH {NADPH) + H

OK~cneHHSSI cpopMa

BOCCT8HOBJleHH8SI cpopMa

CxeMa A

 

 

MeHeHHH 3HepreTHKl1 Xl1MHqecKHX peaKUHH H c

A

TQqKM 3peHHH co6bITl1H B aKTHBHOM ueHTPe.

 

 

A. 3HEPfETWIECKIIE H3MEHEHJUI

NADH + H•

IlPH XIIMWIECKHX PEAKUIDIX

B

CxeMa 6

rne AH2 - nottop aonopona, aoccTattoBJieHH<UI <t:>opMa cy6cTPaTa 1; A - oKMcnettttrui: <t:>opMa cy6CTPaTa 1; B - aKUemop aonopona - BTopoH. cy6CTpaT; BH 2 - aoccTaHOBJiettttaH <t:>opMa cy6CTPaTa 2; NAD+, NADH - oKMcnettttrui: 11 BoccTaHOBJiettttaH <t:>opMbI Ko<l:>epMettTa; E, u E2 - <t:>epMeHTbl.

Ll,Be <t:>epMeHTaTl1BHble peaKU11H, KaTaJIH311pyeMbie <l:>epMettTaM11 E2, corrpmKeHhI .ri:pyr c npyroM rrocpencrnoM Ko<l:>epMeHTa NAD+, cJiyxaruero B KIDK,IJ.OM H3 3THX CJiyqaeB cy6cTpaTOM. )l.TIH rrepBoro <t:>epMeHTa cy6cTpaTOM CJiyxHT OIGICJieHHaH <t:>opMa NAD, B Kaqecrne BToporo cy6cTpaTa BbICTYITaeT ,ll.OHOP BO,II.opo,II.a - rrpHMep IIOCJie,IJ.O-

BaTeJihHbIX peaKUHH, rrpO,II.YKTOM - BOCCTaHOBJieHH<UI <l:>opMa NAD, MH <t:>epMeHTa E2 - ttao6opoT.

B Kaqecrne rrp11Mepa MO.)l{HO paccMoTpeTb cJie-

.ri:y10ruHe corrpH)l(eHHhie peaKUHH (CM. cxeMy Ha rnmi,epa.Tib,II.em.ri;<t:>oc<t:>aT ·.ri:em.ri;po-

JiaKTaT.ri:emnporetta3a.

IV. MEXAHlll3M .QElllCTBllls:t

<l>EPMEHTOB

MexaHH3M .ri:eH.cTBHH <t:>epMeHTOB MOXeT 6wTh paCCMOTPeH c ,II.Byx II03HUHH: c TO'IKH3peHHH H3-

JII06ble XHMmecKMe peaKUHH rrpOTeKaIOT, IIO,ll.- qHHHHCb ,ll.BYM OCHOBHbIM 3aKOHaM TepMO,ll.l1HaM11IG1: 3aKOtty coxpatteHHH 3Heprl1H H 3aKOHY 3HTPOIIHH. Cornactto 3THM 3aKoHaM, o6ruaH 3HeprHH XHMl1qeCKOH CHCTeMbl 11 ee OKpyxeHHH OCTaeTCH IIOCTOHHHOH, rrp11 3TOM XHMHqecK<UI CHCTeMa CTpeMHTCH K CHH)({eHl1IO yrropH,II.oqeHHOCTH (yaeJiwqeHl1IO 3HTPOIIH11). Ll,JIH IIOHl1MaHHH 3HepreTHK11 XHM11qecKOH peaKUHH He,IJ.OCTaTQqHo 3HaTb 3HepreTHqecKUi1: 6aJiaHC BXO,IJ.HIUHX H BbIXO,IJ.HIU11X 113 peaKUH11 peareHTOB, Heo6XO,IJ.11MO yql1TblBaTb 113MeHeHHH 3HeprHH B rrpouecce ,IJ.aHHOH XHMHqecKOH peaKU11H H po.Tib <t:>epMeHTOB B ,IJ.HHaMHKe 3TOro rrpouecca. PaccMOTPHM peaKUHIO pa3JioxeHHH yrOJibHOH KHCJIOThI:

H2C03 ~ Hp + co2.

YroJibH<UI KHCJIOTa CJia6rui:; peaKU11H ee Pa3JIO- )({eHHH rroH,ll.eT rrp11 o6hNHhIX ycJioBH$lX, ec.TIH MoJieKYJihI yrOJibHOH KHCJIOTbl 11MeIOT 3Hepr11IO, rrpeBbllllaIOIUYJO orrpe,II.eJieHHbIH ypoBeHh, Ha3blBaeMbIH 3ttepmeH. aKTHBauHH E. (pHc. 2-10).

3ttepruei1: aKTHBaUHH Ha3bIBaIOT ,ll.OIIOJIHHTeJibHOe KOJIHqecTBO KMHeTHqecKOH 3HeprHH, tteo6xo- ,IJ.HMOe MOJieKYJiaM Beruecrna, qTo6bI OHl1 BCTYITHJil1 B peaKUHIO.

IlpH ,II.0CTH)({eHl1H 3TOro 3Heprenrtl:eCKOro 6apbepa B MOJieKYJie rrpoHCXO,ll.HT H3MeHeHHH, Bbl3hIBaIOIUHe rrepepacrrpe,II.eJieHHe XHMJfqeCKHX CBH3eR R o6pa30BaHHe HOBbIX COe,II.HHeH11H. f OBOPHT' qTQ MOJieKYJihI, 06Jia,uaioru11e E., ttaxo,II.HTCH B rrepexo.ri:- HOM COCTOHHHH. Pa3HHllY 3HeprHH Me)l(,Lly HCXO,II.- HblM pearemoM H2C03 H KOHeqHb1M11 coe.ri:HtteHHHMH H20 11 co2 Ha3bIBaIOT H3Mettem1eM CBOOO,ll.HOH

92

co2 -

rm-14ep8IlbA0n1A-3-¢occpaT

 

 

1,3-6111c¢oc¢orm14epaT

~

 

(AOHOP BOAOPOA0)

 

coo-

 

 

NADH + H+

 

CH3

(npoMe>K}'TO'!HblH

l

 

I

aK4emop BOAOPOAa)

HC-OH

 

C=O

~

 

I

 

I

 

CH3

 

COOH

 

 

 

 

 

naKTaT

 

 

 

 

CxeMa

 

(KOH9'-IHblHaK4emop BOAOPOAa)

 

 

 

 

Ceo6o.QHas:i

 

 

 

 

3Hepri.ts:i

 

 

 

 

 

nepeXO.QHOe

 

 

 

COCTORHl!le

 

 

 

3Hepr111s:i

 

MeHee CTa-

aKT111aa4111111

 

 

 

 

6111nbHOe COCTO-

 

 

 

RHllle

 

 

 

Vl3M0H0Hlll0 cao60AHOH 3H0pn1111

6onee cTa6111nbHOe COCTORHlll0

BpeMs:i

PMC. 2-10. "13MBHBHMe CB060AHOM 3HeprMM npM pa3110)1(8HMM yronbHOM KMCnOTbl.

3Hepnrn: peaKI.1,HH DG. MoJieK)'JihlHp H

6oJiee cTa6HJihHhie Bemecrna, 'leMH2C03, r.e. 06Jia;::i:aIOT MeHhIIIeH: 3HepmeH: H rrpn o6hI'IHhIXycJio- murx rrpaKTll1IeCKH He peampy10T. Bblli:eJIHBIIIMCH 3Hepnrn B pe3yJihTare 3TOH: peaKUHH paccenBaercH B BH.Ue TeIIJia B OKJ>j')!(a10IIIY10cpe;zy.

l.JeM 60JihIIIe MOJieK)'JIo6Jiauaer 3HepmeH:, rrpeBhIIIImomeH: ypoBeHh E0 , reM BhIIIIe CKopocTb XHMH'lecKoH: peaKUHH. IloBhICHTh cKopocTh xnMH'lecKoH: peaKUHH MO)l(HO HarpeBaHHeM. Ilptt 3TOM YBeJIH'IHBaercH3HeprHH pearnpyiomHX MoJieKyJI. 0JJ.HaKO )J.JIH )l(llBhIX opraHH3MOB BhlCOKHe TeMrrepaTypbl ry6ttTeJibHhl, II03TOMY B KJieTKe JJ.JIH ycKopeHHH XHMH'leCKHXpeaKUHH HCIIOJib3YJOTCH cl>epMeHThl. <l>epMeHThl o6ecrre'IHBa10T BhICOKY10 CKOpOCTh peaKUHH rrptt OITTHMaJihHhIX YCJIOBH-

HX, CYIIIeCTBYJOIIIHX B KJieTKe, ITyTeM IIOHH)l(eHHH ypoBHJI E0 TaKHM o6pa3oM, ct.>epMeHThI CHH)l(aJOT BhlCOTY 3HepreTH'leCKOro 6apbepa, B pe3yJihTaTe B03pacTaeT KOJIH'leCTBO peaKUHOHHO-CIIOC06HbIX MOJieK)'JI,CJie,llOBaTeJihHO, yBeJIHqHBaeTCH CKOPOCTh peaKUHH.

B MexaHHJMe cpepMeHTaTHBHOro KaTaJitt3a peIIIa10mee 3Ha'leHHeHMeeT o6pa30BaHHe HeCTOHKHX rrpoMe)l(}'TO'IHhlXcoe,llHHeHHH - cl>epMeHTcy6crpaTHhIH KoMrrJieKc ES, IIOJJ.Bepra10mttH:cH rrpeBpameHH10 B Hecrn6HJihHhIH rrepeXOJJ.HhlH KOMrrJieKc EP, K0Topb1H: rro'ITHMrHoBeHHO pacrrauaercH Ha CB060JJ.HhlH cl>epMeHT H rrpOJJ.YKT peaKUHH.

TaKHM o6pa3oM, 6ttoJiomqecKHe KaTaJIH3aTopbI (cl>epMeHTbl) He H3MeHJI10T CB060)lttyl0 3Hep-

93

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