Bacterial growth inhibition by amniotic fluid. VI. Evidence for a zinc-peptide antibacterial system.

The zinc bacterial inhibitory activity of amniotic fluid is dependent on the presence of a second, organic component contained in amniotic fluid. The second component is heat stable, resists proteolytic digestion, and is present in amniotic fluid throughout pregnancy. Further, the component may be a peptide with a molecular weight of less than 5,000 daltons. Phosphate reversal of amniotic fluid inhibitory activity may result from interference with the organic component rather than zinc.