Hj. Powers et al., VITAMIN-C AT CONCENTRATIONS OBSERVED IN PREMATURE BABIES INHIBITS THEFERROXIDASE ACTIVITY OF CERULOPLASMIN, Free radical research, 22(1), 1995, pp. 57-65
High concentrations of total vitamin C have been measured in the plasm
a of premature infants. At these concentrations ascorbic acid inhibite
d the ferroxidase activity of caeruloplasmin measured directly in vitr
o. The degree of inhibition was dependent on the ratio of ascorbic aci
d: caeruloplasmin. Values for the ratio of vitamin C: caeruloplasmin m
easured in premature babies would be predicted to inhibit ferroxidase
activity by up to at least 80%. Ferroxidase activity measured in the p
lasma of premature babies increased from birth but was significantly l
ower than in plasma collected from adults (<0.001). Plasma ferroxidase
activity was correlated with plasma caeruloplasmin concentration and,
in premature babies only, showed a negative correlation with the rati
o of vitamin C to caeruloplasmin. High levels of vitamin C in prematur
e babies may compromise antioxidant mechanisms and exacerbate oxidant
damage.