Changes in Enzymatic Constitution in Zinc-deficient

The necessity of a metal ion for the activity or synthesis of specific enzymes may be revealed by growing the organism under conditions of the metal deficiency and comparing its enzyme systems with those of normal tissue. Waring and Werkman (1) reported that iron deficiency in Aerobatter indologenes resulted in the suppression of a number of enzymes. Zinc deficiency results in increased acid production by fungi (2), but this has recently been shown to be non-specific, occurring with a number of metal deficiencies (3). Pyruvic carboxylase is absent, in extracts of zincdeficient mycelia, and the assertion has been made that this enzyme may be a zinc protein (4). It has recently been shown that the activity of a tryptophan-synthesizing enzyme (indole + serine -+ tryptophan) is almost completely suppressed in cell-free extracts of zinc-deficient Neurospora mats (5). This effect appeared to be specific for zinc deficiency. The purpose of this paper is to report further the effects of zinc deficiency in changing the content of a number of other enzyme systems in the fungus Neurospora.