PMID- 8837499
OWN - NLM
STAT- MEDLINE
DCOM- 19961211
LR  - 20190909
IS  - 0162-0134 (Print)
IS  - 0162-0134 (Linking)
VI  - 64
IP  - 1
DP  - 1996 Oct
TI  - Role of chromium(IV) in the chromium(VI)-related free radical formation, dG 
      hydroxylation, and DNA damage.
PG  - 25-35
AB  - A reactive Cr(IV) ester was synthesized from a reaction of CrO3 with 
      2,4-dimethyl-2,4-pentanediol as verified by electron spin resonance (ESR) and 
      magnetic susceptibility measurements. ESR spin trapping studies demonstrate that 
      the Cr(IV) ester is capable of generating hydroxyl free radical (.OH) through a 
      Fenton-like mechanism (Cr(IV)+H2O2-->Cr(V)+.OH+OH-) with a concomitant generation 
      of Cr(V) species (g = 1.9787). Cr(IV) caused DNA strand breaks as measured by 
      electrophoretic assays. H2O2 enhanced the DNA strand breaks via .OH formation by 
      a Cr(IV)-mediated Fenton-like reaction. In the Cr(IV)/H2O2 system, formate did 
      not block Cr(V) formation, but prevented DNA damage, indicating that .OH 
      radicals, and not Cr(V), caused the DNA damage. Reaction of Cr(VI) with ascorbate 
      was also used as a source of Cr(IV). Incubation of Cr(VI), ascorbate, and DNA 
      caused DNA strand breaks. A free radical trap, 5,5-dimethyl-1-pyrroline (DMPO), 
      only slightly inhibited the DNA damage. Addition of Mn(II), which inhibited 
      Cr(IV), caused significant protection. H2O2 enhanced the DNA damage via 
      Cr(IV)-mediated .OH radical generation and Mn(II) inhibited the damage, again 
      showing that Cr(IV) and its related .OH generation caused DNA strand breaks. HPLC 
      measurements showed that .OH radicals generated by a Cr(IV)-mediated Fenton-like 
      reaction generated 8-hydroxy-2'-deoxyguanosine from 2'-deoxyguanosine. The 
      results demonstrate that Cr(IV) and its generated .OH radicals are capable of 
      damaging DNA. Moreover, in comparison with Cr(V), Cr(IV) is a more potent DNA 
      damaging agent.
FAU - Luo, H
AU  - Luo H
AD  - Department of Chemistry, West Virginia University, Morgantown 26506, USA.
FAU - Lu, Y
AU  - Lu Y
FAU - Mao, Y
AU  - Mao Y
FAU - Shi, X
AU  - Shi X
FAU - Dalal, N S
AU  - Dalal NS
LA  - eng
PT  - Journal Article
PL  - United States
TA  - J Inorg Biochem
JT  - Journal of inorganic biochemistry
JID - 7905788
RN  - 0 (Free Radicals)
RN  - 0R0008Q3JB (Chromium)
RN  - 9007-49-2 (DNA)
RN  - G9481N71RO (Deoxyguanosine)
SB  - IM
MH  - Chromium/chemistry/*toxicity
MH  - DNA/chemistry/drug effects
MH  - *DNA Damage
MH  - Deoxyguanosine/chemistry
MH  - Electron Spin Resonance Spectroscopy
MH  - Free Radicals/chemistry/toxicity
MH  - Hydroxylation
EDAT- 1996/10/01 00:00
MHDA- 1996/10/01 00:01
CRDT- 1996/10/01 00:00
PHST- 1996/10/01 00:00 [pubmed]
PHST- 1996/10/01 00:01 [medline]
PHST- 1996/10/01 00:00 [entrez]
AID - 0162-0134(95)00241-3 [pii]
AID - 10.1016/0162-0134(95)00241-3 [doi]
PST - ppublish
SO  - J Inorg Biochem. 1996 Oct;64(1):25-35. doi: 10.1016/0162-0134(95)00241-3.