Globin chain biosynthesis in iron deficiency

Globin chain synthesis was studied in seven severely iron-deficient patients before and after treatment with iron. 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 six untreated iron-deficient patients the mean alpha/beta ratio was 1.00+/-SD 0.04. There was therefore no evidence that iron deficiency caused a reduction in alpha/beta ratio. Three patients with beta thalassaemia trait and coexistent iron deficiency had lower alpha/beta ratios before treatment than after treatment with iron. It appeared that iron deficiency had caused reduced alpha chain synthesis in this group. Preliminary experiments have shown that the alpha/beta specific activity ratio of purified haemoglobin A is decreased in iron deficiency, indicating an increase in the size of the free alpha chain pool. It is suggested that iron deficiency may interfere with the proteolytic mechanism normally responsible for the destruction of excess alpha chains. In combined iron deficiency and beta thalassaemia trait, the resulting increase in free alpha chains might act by negative feedback to inhibit further alpha chain synthesis (Blum et al, 1970) thereby reducing the pre-treatment alpha/beta ratio.