MATERIALS AND METHODS

Gastric juice was collected from freshly caught crabs as described by Vonk (2, 3). A bent glass tube was introduced through the mouth and into the stomach, and the stomach contents were carefully sucked into the tube. The juice was freezedried and stored at-20” until used. Taurine, sarcosine, and decanoic acid were purchased from Fluka, Buchs, Switzerland. Sephadex G-25 was obtained from Pharmacia, Uppsala, Sweden, and silica gel G from Merck, Darmstadt, Germany. Chromafogrnphic Methods-Reversed phase partition chromatography (5, 6) was carried out with Phase Systems D (100 ml of 1-butanol as stationary phase and 300 ml of water as mobile phase) and F3 (10 ml of I-heptane per 40 ml of chloroform as stationary phase and 195 ml of methanol per 105 ml of water as mobile phase). Hydrophobic Hyflo Super-Cel was used as support for the stationary phase. Thin layer chromatography of the emulsifiers was performed on silica gel G with phase systems developed by GSinshirt, Koss, and Morianz (7) for the separation of taurine-conjugated bile acids. The water-soluble hydrolysis products of the emulsifiers were chromatographed on thin layer plates with I-butanol-acetic acid-water, 4: 1: 2, or ethanol-ammonia-water, 90: 5: 5, as moving phase (8). These products were also analyzed by two-dimensional paper chromatography according to the method of Redfield (9).