Molecular feature of the nerve growth factor in human serum

Abstract

High molecular weight binding components which bind [ 125I] mouse β nerve growth factor exist in human serum. The binding of β nerve growth factor to the serum components was inhibited at alkaline condition. After gel filtration of human serum on a Sephadex G-150 column at neutral condition, the nerve growth factor-like immunoreactivity was observed in only one peak, differing from the high molecular weight serum components. However, at alkaline condition two peaks with nerve growth factor-like immunoreactivity appeared; one was almost at the position observed at neutral pH, and the other was a new peak eluted approximately to the column volume. these results suggest that there are at least two nerve growth factor-like molecules in human serum and most of the nerve growth factor in the serum exists in a complex form associated with serum components with high molecular weight.