Physiology. In the article “Purification and characterization of a luminal cholecystokinin-releasing factor from rat intestinal secretion” by Alan W. Spannagel, Gary M. Green, Difu Guan, Rodger A. Liddle, Kym Faull, and Joseph R. Reeve, Jr., which appeared in number 9, April 30, 1996, of Proc. Natl. Acad. Sci. USA (93, 4415–4420), the following correction should be noted. Recently obtained sequence data indicated that position 28 of the amino acid sequence for LCRF is glutamate instead of the glutamine originally reported. When we reexamined the original HPLC evaluation of PTH derivatives, it was clear that glutamate had been detected at this position, and that a copying error had been made in preparing a summary of the data. Unfortunately, the sequence reported came from this imperfect summary. We have confirmed that this position is glutamate in ten different and separate analyses. No other changes have been observed at any of the other residues reported in the original article.