Partial amino acid sequence of the precursor of immunoglobulin light chain programmed by messenger RNA in vitro.

The five proteins programmed in a cell-free system by a mouse kappa light chain messenger RNA were labeled with [3H]leucine and subjected to amino acid sequence analyses. In all five proteins, 20 amino acid residues precede the amino terminus of the mature protein, indicating that there is one major point for the initiation of messenger RNA translation. The abundance (30 percent) of leucine residues in the extra piece (leucine at positions 6, 7, 8, 11, 12, and 13) indicates that this moiety is hydrophobic. Furthermore, it seems that the precursor may have an additional extra piece at the carboxyl terminus.