Globin Chain Biosynthesis in Iron Deficiency

Abstract

Globin chain synthesis was studied in 7 severely Fe-deficient patients before and after treatment with Fe. There was no appreciable difference between the individual pre- and post-treatment .alpha./.beta. specific activity ratios and the mean .alpha./.beta. ratio for each group was 1.00 .+-. SD 0.04. In a further 6 untreated Fe-deficient patients the mean .alpha./.beta. ratio was 1.00 .+-. SD 0.04. There was no evidence that Fe deficiency caused a reduction in .alpha./.beta. ratio. Three patients with .beta. thalassemia trait and coexistent Fe deficiency had lower .alpha./.beta. ratios before treatment than after treatment with Fe. Fe deficiency apparently had caused reduced .alpha. chain synthesis in this group. Preliminary experiments showed that the .alpha./.beta. specific activity ratio of purified Hb A is decreased in Fe deficiency, indicating an increase in size of the free .alpha. chain pool. Fe deficiency may interfere with the proteolytic mechanism normally responsible for destruction of excess .alpha. chains. In combined Fe deficiency and .beta. thalassemia trait, the resulting increase in free .alpha. chains might act by negative feedback to inhibit further .alpha. chain synthesis, thereby reducing the pre-treatment .alpha./.beta. ratio.