Quantitative estimation of the damage to the gamma irradiated haematin in aqueous solutions

A C T A U N I V E R S I T A T I S L O D Z I E N S I S FOLIA BIOCHIMICA ET BIOPHYSICA 2 , 1983

Roman Ł u k asz e w icz , M ieczy sław P u c h a ła , Wanda Leyko QUANTITATIVE ESTIMATION OF THE DAMAGE

TO THE GAMMA IRRADIATED HAEMATTN IN AQUEOUS SOLUTIONS

The s t a t i o n a r y r a d i o l y s i s o f 0 .1 N KOH a qu eou s s o l u -t i o n s o f h aem a-tin was c a r r ie d o u -t in o r d e r -t o d e -term in e -th e e f f e c t i v e n e s s o f th e in d i v id u a l r a d i c a l s . The sam p les were i r r a d i a t e d a l s o in th e p re s e n c e o f f r e e r a d i c a l s c a v e n g e r s. The r a d i o s e n s i t i v i t y o f h aem atin was d eterm in ed u n d er th e i n v e s t i g a t e d c o n d it io n s and th e r a d i a t i o n y i e l d o f h aem atin was a l s o e s t im a te d . R e s u l t s o b ta in e d f o r d i f f e r e n t r a d i -c a l s were -com pared. The e f f e c t i v e n e s s o f h y d ra ted e le c t r o n s and h yd roxyl r a d i c a l s seems to be th e h ig h e s t , w h ile th e r o l e o f s u p e ro x id e a n io n and th e e th a n o l r a d i c a l i s r a t h e r s m a l l. In th e p r e s e n c e o f r a d i c a l s o f " o p p o s i t e " n a tu r e , o x i d i z in g and r e d u c in g , " r e c o n s t r u c t i o n " r e a c t i o n was o b se rv e d .

In tr o d u c ti o n

The i n f l u e n c e o f i o n i z in g r a d i a t i o n upon haeme h a s u s u a l ly been o b se r v e d in o r d e r t o d ete rm in e th e " s o - c a l l e d " p r o c e s s o f "apoenzyme p r o t e c t i v e e f f e c t " f o r some o f h a em op rote in s [1 0 , 2 1 ]. Some w orks d e a l in g w ith th e k i n e t i c s o f r a d i o l y s i s o f p o r p h y rin s had t o b e c a r r i e d o u t u n d er c o n d i tio n s p r o t e c t i n g a g a i n s t a g g r e -g a t i o n , which was n e c e s s a r y f o r k i n e t i c in fo r m a tio n s [ 2 0 ] . In th e se s o lv e n t m ix tu re s th e p rim ary y i e l d o f r a d i c a l s rem ained unknown. I t was d i f f i c u l t , t h e r e f o r e , to d eterm in e th e e f f e c t i -v e n e s s o f th e in d i -v i d u a l r a d i c a l . The p r e s e n t work i s co ncerned m ain ly w ith th e q u a n t i t a t i v e a s p e c t o f h aem atin r a d i o l y s i s and th e c o n tr i b u t io n o f r a d i c a l s t o th e d e s t r u c t io n p r o c e s s . As th e

s t r u c t u r e o f p o r p h y r i n s ’ s o l u t i o n s i s s t i l l d i s c u s s e d we. r e s i g -ned t o c a l c u l a t e th e d e g re e o f a g g r e g a t i o n , and e x p r e s s e d a l l d a ta p e r gram atom o f p o r p h y r in s ’ ir o n . The b a s i c method a p p li e d in o u r e x p e rim e n ts c o n s i s t e d o f a d d i t io n o f f r e e r a d i c a l sc a v en -g e r s t o th e i r r a d i a t e d s o l u t i o n s , which c a u se d l i m i t a t i o n o f ch osen r a d i c a l s down t o v a l u e s which c o u ld be n e g l e c t e d . R e s u lt s o f r a d i o l y s i s p erform ed in th e p re s e n c e o f few r a d i c a l s resp on -s i b l e f o r th e f i n a l e f f e c t a llo w e d to e s ti m a t e th e r o l e o f in -d iv i-d u a l r a d i c a l s c o n c er n in g h aem atin d e s t r u c t i o n u n d er g ive n c o n d it io n s .

M a t e r ia l s and methods

The r e a g e n t s u se d were A .R .- g r a d e , (PO C h-G liw ice), w ith o u t f u r t h e r p u r i f i c a t i o n . S o lu t i o n s were p r e p a r e d u si n g b i - d i s t i l l e d w a te r . T rad e h aem atin (PO C h -d liw ice) was p u r i f i e d a c c o rd in g to th e method o f Shemin [ 2 5 ] . H aem atin s o l u t i o n s were p r e p a re d by w eig h t in 0 .1 N KOH, and checked s p e c t r o f o t o m e t r i c a l l y a t 385 nm, a f t e r 15 m in u tes . The p rim a ry h aem atin c o n c e n t r a t io n e q u a l le d 2 * •1 0 " 3 M (E^g^ = 58 9 0 0 ), a v e r a g e sta n d a r d d e v i a t io n was ab ou t

5%.

Sam p les were p r o t e c t e d from l i g h t . The i r r a d i a t i o n was c a r -r i e d ou t in an io n iz i n g chambe-r by Co^° so u -rc e a t -room tem p e-ra- era-t u r e in an aera-tm osp h ere o f a rg o n , a i r , oxy gen , o r n i t r o u s o x id e . E th a n ol ( 2 ’ 10- M) and sodium fo rm a te (10 “ M) were a p p li e d a s a d d i t i o n a l r a d i c a l s c a v e n g e r s. The d ose r a t e was 0 .8 M rad /h, th e d o s e s ran g e d from 0 .1 t o 4 M rads. The a b so rb a n c e was m easured in 1 cm c u v e t t e s a f t e r d i l u t i n g sa m p les w ith a i i> - s a tu r a t e d 0 .1 N KOH, u s in g S p ec o rd UV-VIS and VSU-2p sp e c tro p h o to m e ter s (-C arl- - Z e i s s , J e n a ) .

R e s u l t s and d i s c u s s io n

The i r r a d i a t i o n c a u se d an a l t e r a t i o n o f h aem atin sp ec tru m , p a r t i c u l a r l y s i g n i f i c a n t in th e S o r e t b and . S p e c t r a a f t e r , and b e f o r e i r r a d i a t i o n a r e shown in F i g . 1 .

-lu e (a b so rb a n c e a t 385 nm). B e ca u se o f a g g r e g a t e s which may be formed u n d er s t u d i e d c o n d iti o n s [ 6 , 7 , 8 ] th e L a m b ert-B ee r law do n o t a p p ly in a l k a l i n e h aem atin s o l u t i o n s . However, d e v i a t i o n s o b se rv e d i n th e ra n g e s t u d ie d d id n o t e xc ee d 20

%,

what would co n firm h y p o th e s is t h a t an a l t e r a t i o n o f th e m o lar e x t i n c t io n c o e f f i c i e n t d e c r e a s e s f o r p o r p h y r in s ’ s o l u t i o n s f o r pH h ig h e r th an 11 [ 7 , 8 ] . R a d i o l y s i s o f h aem atin s o l u t i o n s was p erform ed in ou r e x p e rim e n ts u n d er c o n d it io n s h av in g w ell known p rim a ry r a d i c a l s r a d i a t io n y i e l d . R e s u l t s p r e s e n te d in F i g . 2 i n d i c a t e t h a t th e r e i s a s i g n i f i c a n t dependence betw een c o n d iti o n s o f r a -d i o l y s i s an-d -d eg ree o f -d e s t r u c t i o n .

F i g . 1 . A b so rp tion s p e c t r a o f h aem atin in th e v i s i b l e ran g e f o r d i f f e r e n t d o se s o f - r a d i a t i o n ( a i r atm osp h ere )

Widma a b s o r p c j i hematyny w z a k r e s i e w idz ialny m d l a różn ych dawek p rom ienio w an ia y (w a tm o sf e r z e p o w ie t rz a )

O n e K T p u n o r j io n e H H H b h ^ h m o t o c B e T a re M a T H H O M j u r a p a 3 H h ix ^ 0 3 - ¡ f- o 6 ji y » i e H H H ( b a T M o c t J > e p e B 0 3 jn y x a )

A cc ord in g t o B u t l e r , E v e r s e t a l . [ 9 , 1 7 , 2 0 ] some r a d i c a l s may r e a c t w ith h aem atin l e a d i n g to p h lo r in d e r iv a -t i v e s , e . g .

i i . „ . I I

Fe.,_chaem I I I Fe_{1 haem}

As a l l th e s e in te r m e d ia te s m ig ht have an

p h lo r in + F e ’1"1" (1 ) a p p r e c ia b l e a b s o rp

-t i o n in -th e S o r e -t b and , we fo und e x p e r im e n ta l ly , com parin g s p e c -t r a o b -ta in e d f o r d i f f e r e n -t d o s e s o f i r r a d i a -t i o n , -th a -t j u s -t 385 nm i s th e b e s t w av elen gth f o r c h a r a c t e r i z i n g p o s t - i r r a d i a t e d chan-g e s . The a p p li e d method was a l s o q u ic k enough t o a v o id th e p ro -blem o f slow s p e c t r a l c h a n g es d e s c r ib e d a s " a g e in g " o f h aem atin

s o l u t i o n s . The in fl u e n c e o f f a s t p r o c e s s e s a s g re en com plex f o r -ming [ 5 ] e lim in a te d by w a iti n g u n t i l was a b so rb a n c e o f sam p les was s t a b l e . S in c e th e r a t e c o n s ta n t o f a u t o o x i d a t io n was eq u al to 5 .6 x ID- 4 min“ 1 [7] th e i n f lu e n c e o f t h i s r e a c t i o n c o u ld be n e g l e c t e d . Our o b s e r v a t io n s o f h aem atin s o l u t i o n s s t o r e d f o r s e -v e r a l w eeks c on firm ed th e r e s u l t s o b t a in e d by B r o w n e t a l., how ever, a l t e r a t i o n s were s lo w e r (th e d e c r e a s e o f a b so rb a n c e a t 460 nm e q u a l le d a s l i t t l e a s 6% a f t e r 4 w ee k s). As we e x p r e ss e d a l l d a ta c o n c e rn in g h a em atin s o l u t i o n s p e r gram atom o f p orp h y r-i n s r-i r o n , a l l c a lc u l a t e d c o e f f r-i c r-i e n t s sh o u ld be u n d e r sto o d t o be r e l a t i v e . The e s t im a ti o n o f th e c o m p a ra tiv e a c t i v i t y o f in

-T a b l e 1

R a d i c a ls ’ r a d i a t i o n y i e l d s and i n i t i a l y i e l d s

o f h aem atin d e s t r u c t i o n ^.r ) u n d er d i f f e r e n t c o n d iti o n s o f r a d i o l y s i s

W ydajność rodnikowa a w a r t o ś c i w y d a jn o śc i d e s t r u k c j i hematyny (Gd e s t r ) w z a le ż n o ś c i od warunków r a d i o l i z y

PaçaaqHOHHo-xHMH'iecKHfi b h x o ą a 3<ï>$eKTHBH0CTb ąecTpyiatHH reMamHa (Gd e s t r ' B 3aBHCHM0CTH 01 ycJioB«» paąHOJiH3a

Condi-t i o n s

-i

Oxygen A ir1 _{e th a n o l}A ir - _HCOONaA ir

-,

n2o1 Argon1 Argon HCOONa °0H 3 .1 7 3 .1 7 0 0 4 .6 0 3 .1 7 0 2 .7 3 2 .7 3 2 .7 3 5 .9 0 0 .4 0 0 0 ° E t 0 0 3 .1 7 0 0 0 0

%

0 0 0 0 0 2 .7 3 2 .7 3 G ° _{d e s t r}4 0 .1 0 0 0 .1 0 0 0 .0 4 5 0 .0 4 5 0 .1 2 0 0 .0 2 0 0 .0 7 2 1 2 W ithout a d d it i o n a l s c a v e n g e r s a d d e d ; EtOH c o n c e n t ra t io n e q u a le d to 2 x 1 0 -2 M; 3 HCOONa c o n c e n t r a t io n eq u a l t o 0 .0 1 M; ^a-v e ra g e s ta n d a r d d e ^a-v ia t io n e q u a le d to 10%

d iv id u a l r a d i c a l s upon th e p r e s e n c e o f o th e r s i s in d ep en d en t o f th e s t r u c t u r e o f s o l u t i o n s u n t i l s t r u c t u r e d i f f e r e n c e s c a u se d by d i f f e r e n t c o n d i tio n s a r e n e g l i g i b l e . The r a t i o o f a b s o rb a n c e s a t 580 nm t o 540 nm ta k e n a s a m easure o f complex fo rm a tio n [A , 5 ] d id n o t depend s i g n i f i c a n t l y on th e c o n d iti o n s a p p li e d and was 0 .8 + 0 .1 0 . R a d ic a l r a d i a t i o n y i e l d v a l u e s sum m arised in T ab. 1 were ta k en from l i t e r a t u r e a c c o r d in g to a u t h o r s i n v e s t i g a t i n g th e r a d i o l y s i s o f sy ste m s s i m i l a r to o u rs [1 1 , 1 2 , 1 3, 1 4, 15 , 1 6 , 18 , 1 9 , 2 2 ] .

— o r atmosphere without scavengers added • -•»... argon atmosphere without scavengers added

- f r

—tr

air atmosphere in the presence of ethanol [2*10?M1 - o - o - air atmosphere in the presence of HCOONa |K)'?M )

m

nitrous oxide atmosphere without scavengers added ■»

•

oxygen atmosphere without scavengers added

argon atmosphere in the presence of ethonoi 12 «10 H i

F i g . 2 . The p e r c e n t d e c r e a s e o f c o n c e n tr a tio n o f i r r a d i a t e d h ae-m atin s o l u ti o n a s a f u n c tio n o f th e d o se

Prezentowy sp ad ek s t ę ż e n i a naprom ieniow anych roztworów hematyny w f u n k c j i dawki

n p o i ie H T H o e n o H H s e H H e K O H n e H ip a m m o C jry u e H H H X p a c iB o p o B r e n ia T H H a

The v a l u e s o f h aem atin i n i t i a l d e s t r u c t i o n y i e l d p r e s e n te d in T ab . 1 were c a l c u l a t e d from e x p e rim e n ta l d a t a - s l o p e o f th e d o s e e f f e c t c u r v e s f o r a d ose ran g e o f 0 . 2 - 0 . 4 Mrad, a c c o r d in g to F i g . 2 .

C o n d itio n s o f r a d i o l y s i s

Argon atm osp h ere w ith o u t a d d i t i o n a l f r e e r a d i c a l s c a v e n g e r s

A ll d a ta a r e b a se d on r e s u l t s o b ta in e d by H a i s s i n s - k y [ 1 8 , 1 9 ]. The in f l u e n c e o f "H r a d i c a l s i s o m itte d a s th ey a r e c o n v e rte d t o h y d ra te d e l e c t r o n s in th e a l k a l i n e medium.

•H + OH“ - * e ” + Ho0 _aq ( 2 ) k„ - 2 x 107 M“ 1 s “ 1

_c.

The y i e l d o f e” q was c o r r e c t e d a c c o rd in g t o ( 2 ) . The s h o u l -d e r on th e -d o s e - e f f e c t c u rve a t a b o u t th e -d o se o f 0 .1 Mrad i s p r o b a b ly th e r e s u l t o f an in c o m p lete d e a e r a ti o n .

Oxygen and a i r atm osp h e res w ith o u t a d d i t i o n a l s c a v e n g e r s added

T ak in g p rim ary r a d i a t io n y i e l d s a c c o rd in g t o H a is s in s k y , f i -n a l y i e l d s were c o r r e c t e d due t o th e r e a c t i o n o f i n t e n s i v e s c a -v en g in g o f h y d ra te d e l e c t r o n s by oxyg en : ' e“ q + 02 - *0 “ ( 3 ) k? . 1 .8 8 x 1 0 10 [ 1 9 ] P o s s ib l e r e a c t io n *H + 02 - HO“ ( 4 ) k4 = 1 .9 x 1010 [ 2 ]

which may compete w ith (4 ) l e a d s a l s o t o 02 , b e c a u se H02 d i s s o c i a -t e s in -th e a l k a l i n e medium.

*H02 , H+ + *0 2 ( 5 ) pK^ * 4 .8 8 [ 2 3 ]

and d o es n o t in fl u e n c e th e f i n a l r e s u l t e i t h e r from th e q u a l i t a -t i v e o r q u a n -t i -t a -t i v e p o i n -t o f view .

The i r r a d i a t i o n in th e a tm osp h eres o f oxygen and a i r was c an - r l e d o u t in p a r a l l e l in o r d e r t o e x c lu d e th e in f lu e n c e o f n i t r o -gen o x id e s which m igh t be g e n e ra te d in a i r d u rin g i r r a d i a t i o n . But such an in f l u e n c e was n o t o b s e rv e d .

NgO atm osp h ere

The main r e a c t i o n which o c c u r re d was th e c o n v e r sio n o f hy-d r a te hy-d e l e c t r o n s to h y hy-d ro xy l r a hy-d i c a l s .

' e~q + N2 0 + H2 0 - ‘ OH + OH- + N2 ( 6 ) [ 1 3 ] A cc ord in g t o many a u t h o r s th e c o n c e n t r a t io n o f OH r a d i c a l s i s h ig h enough to form 02 - e i t h e r in th e OH-OH rec o m b in a tion p r o c e s s o r in r e a c t i o n s between OH r a d i c a l s and i t s d e p ro to n ate d fon n 0“ . Many mechanisms o f r a d i o l y s i s o f N2 0 - s a t u r a t e d a l k a l i n e s o l u t i o n s h ave been c o n s id e r e d up to now, and a r e s t i l l d is c u s -s e d . We to ok Gq h * 4 .6 0 and G0~ 0 .4 0 a c c o rd in g t o D a i n- t o n e t a l . [ 1 3 ] , R a b a n i e t a l . [ 2 3 ] and Z e h a v i e t a l . [ 2 6 ] . •OH + ‘ OH ---~ H2 °2 ( 7 ) H2 °2 + *0 ” --- O ' + H2 0 ( 8 ) A ir + HCOONa

The f i n a l r e s u l t s c o rre sp o n d w ith th e s i t u a t i o n , where r e a c -t i o n s ( 3 ) , ( 4 ) o c c u r and a f te r w a r d s OH r a d i c a l s a r e tra n sfo rm ed to *0 2 r a d i c a l s .

'OH _oxygen — *0 “ ₂ ( 9 )

and su p e r o x id e a n io n r a d i a t i o n y i e l d i s e q u a l t o th e sum o f a l l p rim ary form ed r a d i c a l s , b e in g th e o n ly f r e e r a d i c a l p r e s e n t in s i g n i f i c a n t q u a n t i t i e s . The d e t a i l e d d i s c u s s i o n was p r e s e n t e d by D r a g a n i <5 e t a l . [ 1 6 ] . A ir + e th a n o l S e d d o n and A l l e n [ 2 4 ] fou n d t h a t f i n a l r e s u l t s o f o x y g e n -s a t u r a te d e th a n o l s o l u t i o n s to form in g "02 and e th a -n o l r a d i c a l s i-n r e a c t i o -n s

e; q ° 3 - . » • ( ) " , (1 0 ) [ 2 4 ]

• 0 H ^ 0 i L ^ -Retrianbl> (11) [ 2 4 ]

Argon + HCOONa

. H ydroxyl r a d i c a l s r e a c t v e r y e f f i c i e n t l y w ith fo r m a te io n s HC00" + ‘ OH = OH- + H2 0 + COO" (1 2 ) and ’ e " _aq rem a in s main a c t i v e s p e c i e ,

C a lc u l a t io n s The e s t im a t io n o f

G,

. o f h a em atin b a se d on th e d e f i n i - d e s t r t i o n o f th e d e s t r u c t io n y i e l d (th e amount o f m o le c u le s damaged by 100 eV o f i o n i z in g r a d i a t i o n e n e rg y ) [ 1 ] . _ 109 • Ac d e s t r

---w here: c - th e change o f h aem atin c o n c e n t r a tio n (M ); Ax - th e d o se in r a d s which c a u s e d th e change o f c o n c e n t r a t io n A c. In o r d e r t o e v a lu a te q u a n t i t a t i v e l y th e r o l e o f in d i v id u a l r a d i c a l s i n th e r a d i o l y s i s , th e r a t i o o f th e y i e l d o f d e s t r u c t i o n c a u s e d by any r a d i c a l to th e y i e l d o f t h i s r a d i c a l was c a l -c u l a t e d f = ^ s t r (1 4 ) G w here: Gd e s t r " th e r a d i a t i o n y i e l d o f d e s t r u c t io n c a u se d by th e -.o r a d i c a l c a u se d by th e r a d i c a l form ed w ith th e y i e l d e q u a le d G

T h is m agnitud e was c a l l e d in ou r work "th e e f f e c t i v e n e s s coe-f coe-f i c i e n t " o f an in d i v i d u a l r a d i c a l , b e c a u s e i t i n d i c a t e r a d io -s e n -s i t i v i t y o f h aem atin t o t h i -s r a d i c a l . Under c o n d i ti o n s where we can assum e t h a t th e e f f e c t i s c a u se d by one r a d i c a l o n ly , e q u a tio n

'd e s t r (1 5 ) i s t r u e . When r e s u l t s c o u ld be a t r i b u t e d to s e v e r a l s p e c i e s th e t o t a l e f f e c t i s e q u a le d to th e sum o f d e s t r u c t io n s c a u se d by a l l r a d i -c a l s , a s f a r a s i n t e r - r a d i -c a l s i n t e r a -c t i o n i s n e g l i g i b l e . d e s t r

(

16

)

B a sed on e q. (1 6 ) a p p rox im a te v a l u e s o f " f " may be d eterm in ed i f G^eg-tr i s known ( in o u r e xp e rim e n ts Gd e s t r was u s in g to r e -l a t i v e c a l c u l a t i o n s o n ly , b e c a u se we d id n ot e s t im a t e p e r c e n t o f d im e rs in s o l u t i o n , and we d id n o t know e x a c t l y t h e r e f o r e mol- l a r c o n c e n t r a t io n ) - c ( s e e eq . ( 1 3 ) ) . However r e s u l t s o f c a l -c u la t i o n s a r e in d ep en d en t on r a d i o l y s i s -c o n d iti o n s s i n -c e p r e s e n t r a d i c a l s a r e a l l o x i d i z i n g , ( o r a l l r e d u c in g , e . g . r e s u l t s ob-ta in e d in sy ste m s: Argon + HCOONa and Argon + EtOH a r e th e same).

Only e xp e rim e n ts w ith a r g o n s a t u r a t e d s o l u t i o n s l e a d to d i f -f e r e n t d a ta ( s e e T ab . 2 ) .

T a b l e 2

V alu e s o f th e e f f e c t i v e n e s s c o e f f i c i e n t s o f h aem atin d e s t r u c t io n c a l c u l a t e d from th e v a l u e s o f G ^ t r o b ta in e d in th e p r e se n c e

o f r a d i c a l s h a vin g s i m i l a r n a tu r e

lfy d a jn ość ak ty w n o śc i d e s tr u k c y jn e j wobec hematyny wykazywana p r z e z r o d n ik i w warunkach o b e c n o śc i rodników in n yc h, a l e o t e j sam ej n a tu r z e 3 ii> $ e K T H B H 0 C T i> ^ e c T p y K U H H r e M a T H H a B t m n c j i e H H u e H a 0 C H 0 B e 3 H a q e H H # Gdesłr n o ji y n e H H u x b n p H c y Tc t b h h p a u n n a J iO B c x o a h oK n p a p o j ih i R a d ic a l •OH 6aq Re th a n o l "°2 E f f e c t i v e n e s s c o e f f i c i e n t 0 .0 2 5 5 0 .0 2 6 4 . 0 .0 0 7 6 0 .0 0 7 6

C o n c lu sio n s

1 . A p p l ic a t io n o f m ath em a tic ia n m ethods may a llo w t o detei>- mine some p a r a m e t e r s, l i k e r a d i c a l s ’ a c t i v i t y to many compounds, o r r a d i a t i o n d e s t r u c t io n y i e l d - in e a s y way. In t h a t work we e s -tim a te d m ain ly r e l a t i v e v a l u e s , how ever i t sh o u ld be p o s s i b l e to found a l s o a b s o l u t e d a ta , by com paring ou r r e s u l t s w ith th e d a ta c o n c ern in g s t r u c t u r e o f i n v e s t i g a t e d s o l u t i o n s .

2 . R a d i o s e n s i t i v i t y i s d i f f e r e n t o f t e n to v a r io u s r a d i c a l s . F o r h ae m a tin e a l k a l i n e s o l u t i o n s s e n s i t i v i t y to r a d i c a l s formed d u rin g w a te r r a d i o l y s i s i s th e h ig h e s t in th e c a s e o f h y d ra te d e l e c t r o n s and h y d rox y l r a d i c a l s , w h ile th e r o l e o f su p e ro x id e an io n seem s to be r a t h e r s l i g h t (*® a q : " 0H ' '° 2 = ”' * 00 5 '••0° •

: 0 .2 9 ) .

3 . S i m i l a r r e s u l t s o b ta in e d f o r s y s te m s : HCOONa-water, and EtOH -water in th e p r e s e n c e o f oxygen may i n d i c a t e t h a t eth a n o l r a d i c a l s , u s u a l l y re d u c in g s p e c i e s a r e c o n v e rte d in o x y g e n s a tu -r a te d s o l u t i o n s in t o o x i d i z in g -r a d i c a l s . 4 . V ery s l i g h t d e s t r u c t i o n e f f e c t o b se rv e d in sy stem a rg o n - -w a te r, w ith o u t a d d i t i o n a l sc a v e n g e r s add ed s u g g e s t s f a s t i n t e r -a c t i o n between p r e s e n t s p e c i e s formed in th e c o u rs e o f r a d io l y -s i -s , b e c a u -se r a d i c a l -s l i k e h y d ra te d e l e c t r o n -s o r h y d rox y l -ra d i-c a l s u s u a l l y r e a i-c t w ith h a em atin v ery e f f i i-c i e n t l y . The e f f e i-c t de-s c r ib e d above may be due t o f a de-s t " r e c o n de-s t r u c t i o n " p r o c e de-s de-s e de-s o f h a em a tin , re d u c in g in one s t e p and th en b e in g r e o x i d i z i n g .

5 . G e n e ra tio n o f n it r o g e n o x i d e s , un d er g iv e n c o n d iti o n ( a i r a tm o sp h ere, d o se r a t e o f 0 .8 M ra d /h ) was n o t o b s e rv e d . REFERENCES [1 ] A l t m a n K. J . , B e r g e r G. B . , 0 k a d a S . , R a d ia tio n B io c h e m istry 1_ (1 9 7 0 ). [ 2 ] A n b a r M ., N e t a P ., I n t . J . A p pl. R a d ia t, I s o -t o p e s 1 8 , 493 (1 9 6 7 ).

13] B e h a r D ., C z a p s k i G ., R a b a n i J . , D o r f m a n L . M ., J . Phys. Chem. 7 4 , 3209 (1 9 7 0 ). [4 ] B 1 a u e r G ., B ioch im . B io p h y s. A cta 7 9 , 547 (1 9 6 4 ). [5 ] B l a u e r G. , Z v i l i c h o v s k y B . , BBA 2 2 1 , 442 (1 9 7 0 ). [6 ] B r o w n S. B. , D e a n T. C. , J o n e s P . , B io - chem. J . 1 1 7 , 733 (1 9 7 0 ). [ 7 ] B r o w n S. B . , J o n e s P . , S u g g e t i A., T ra n s. F a ra d . S o c . 6 4 , 986 (1 9 6 8 ). [ 8 ] B r o w n S. B. , L a n t z k e I . R . , Biochem. J . 1 1 5 , 279 (1 9 6 9 ). [ 9 ] B u t l e r J . , T ra n s . F a r a d . S o c . 7 2 , 1391 (1 9 7 6 ). [1 0 ] C r i p p a P. R ., V e c 1 i A ., B io p h y s. Jo u m . 10 , 269 (1 9 7 0 ). [1 1 ] C z a p s k i G. , B i e l s k i G. H. J . , J . Phys. Chem. 6 7 , 2180 ( 1 9 6 3 ) . [1 2 ] C z a p s k i G. , D o r f m a n L . M . , J . Ph y s. Chem. 6 8 , 1169 (1 9 6 4 ). [1 3 ] D a i n t o n F. S. , P e t e r s o n D. B . , P ro c . Roy. S o c . S e r . A 2 67 , 443 (1 9 6 2 ). [1 4 ] D r a g a n i d I . G. , N e n a d o v i d M. T . , D r a - g a n i ć Z. D ., J . Phys. Chem. 7 3 , 256 4 (1 9 6 9 ). [1 5 ] D r a g a n i e I . G. , D r a g a n i ć Z. D ., J . Phys. Chem. 7 3 , 2571 (1 9 6 9 ) . [ 1 6 ] D r a g a n i ć I . G . , D r a g a n i ć Z . D . , K o s a - n i ć M ., J . P hy s. Chem. 7 0 , 1418 (1 9 6 6) . [1 7 ] E v e r s E . , T r a n s . F a ra d . S o c . 7 4 , 418 (1 9 7 8 ). [1 8 ] H a i s s i n s k y M ., J . Chim. Ph ys. 6 0 , 402 (1 9 6 3 ). [1 9 ] H a i s s i n s k y M. , P a t i g n y P ., J . Chim. P h ys. 5 9 , 633 (1 9 6 2 ). [2 0 ] H a r e l Y. , M e y e r s t e i n D ., J . Amer. Chem. S o c . 9 6 , 2720 (1 9 7 4 ). [2 1 ] L y n n K. R . , R a o u 1 t A. P . , I n t . J . R a d i a t . B i o l . 2 4 , 25 (1 9 7 3 ). [2 2 ] R a b a n i J . , M a t h e s o n M. S . , J . Phy s. Chem. 7 0 , 761 (1966)-. [2 3 ] R a b a n i J . , N i e l s e n S . 0 . , J . Ph ys. Chem. 7 3, 3736 (1 9 6 9 ).

[ 2 4 ] S e d d o n W. A ., A l l e n A. 0 . , J . Ph y s. Chem. 7 1 , 191 4 (1 9 6 7 ).

[ 2 5 ] S h e m i n J . D ., c i t e d a f t e r : C o l o w i c k S. P. , K a p l a n N. A ., Methods in En z ym ologie, v o l . IV, New Y ork, 643 (1 9 5 7 ). [2 6 ] Z e h a v i D. , R a b a n i J . , J . Ph y s. Chem. 7 5 ,1 7 3 8 (1 9 7 1 ). [ 2 7 ] Y o n g F . C . , K i n g T. E . , J . B i o l . Chem. 2 4 4 , 509 (1 9 6 9 ). D epartm ent o f B io p h y s ic s I n s t i t u t e o f B io c h e m istry and B i o p h y s ic s U n iv e r s it y o f Łódź

Roman Ł u k asz e w ic z , M ieczy sław P u c h a ła , Wanda Leyko OCENA ILOŚCIOWA DESTRUKCJI NAPROMIENIONYCH PROMIENIAMI

WODNYCH ROZTWORÓW HEMATYNY

W p ra c y prowadzono r a d i o l i z ę roz tw oru hematyny w 0 ,1 N wodnym KOH. W c e lu o sza c ow a n ia p r o m ie n io c z u ło ś c i hematyny wobec p o s z c z e -g ólny c h rodników z asto sow a n o dodawanie do n ap rom ienian e-g o ro z -tw oru z m ia ta c z y wodnych rod ników . A n a liz u ją c otrzym ane w yn iki o- k r e ślo n o w ie lk o ść w y d a jn o śc i r a d i a c y jn e j d e s t r u k c j i hem atyny, l i -c z o n e j na gramoatom ż e l a z a p o rfiry n o w e g o , a ta k ż e o k r e ślo n o p r o - m ie n io c z u ło ść hematyny w bad anych w arunkach. Porównanie wpływu różn ych rodn ików , p o w sta ją c y c h w p r o c e s i e r a d i o l i z y wody wskazu-j e , ż e w a l k a l ic z n y c h warunkach n a wskazu-jw ię k sz e n i s z c z ą c e d z i a ł a n i e na hematynę w y ka z u ją: r o d n ik i h yd roksy low e i e le k tr o n y uw odnione, p o d c z a s gdy wpływ anion orodn ików ponadtlenkow ych i rodników e t a -nolowych j e s t n ie z n ac z n y . W ydajność r a d i o l i z y s z c z e g ó l n ie m alał a , gdy w środ o w isku z n ajd o w a alały s i ę je d n o c z e ś n ie r o d n ik i o u t l e -n ia ją c y m i red uku jącym c h a r a k t e r z e , co może być spowodowane z a

PoMciH JlyicameBim, Me^HCJiaB Ilyxauia, BaHj;a JlefiKO

KOJIJWECTBEHHAH OUEHKA flEGTPyKUHH 'j'-OEJiyHEHHUX BOflHhlX PACTBOPOB TEMATHHA

B paÔOTe onpenejisjiH 3<J4ieKTHBHOCTb oi^e^bHNX panHKanoB b npo-

u ec ce panHçjiH3a pacTBopa reniaTHHa 0, l h KOH, n p H M e H H H M e T o n " c M e - TaTejieit" c boÔo^h mx pa^HKanoB. y c T a H O B J i e H O p a n H O M y B C T B H T e ^ b H O C T b reMaiHHa b H C C Ji e r ç y e M b i x y c J i o - b h h x h p a n H a u H O H H O - x H M j m e c K H ü b u x o a ^ e c i p y K U H H r e M a i H H a . C p a B H H B a - J i H c b p e 3 y Æ b T a T h i , n o a y M e H H u e x j i k 0 T , n e j i b H H X p a n H K a J i O B . 3<Jx{>eKTHB- H O C T b T H U p a T H p O B a H H O r O 3 J i e K T p O H a H T H U p O K C H J I b H O rO p a j ; H K a j i a H B J I f l - 6 T C H Ca MO ft BhI CO KO Â , B TO Bp e MÆ K a K BJIH HHH e C y n e p O K C H U H O r O H 3 T a H 0 —