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A solution of 500 mg of (±)-11-deoxyprostaglandin Ei was dissolved in 30 ml of methanol and solid sodium borohydride was added portionwise until no more starting material could be detected by tic analysis (40% ethyl acetate-60% hexane). The reaction solution was poured into water and extracted with ethyl acetate. The organic phase was washed with brine and dried over anhydrous sodium sulfate. The solvent was eliminated under reduced pressure and the residue purified via preparative tic to yield 303 mg of (±)-11-deoxyprostaglandin Fia methyl ester and 98 mg of its 9/3 epimer. Basic hydrolysis of these compounds in the usual manner yielded (±)-ll-deoxyprostaglandin Fia [mp 97-98.5°; ir 3400 (br), 3160 (br), 2970 (sh), 2930 (s), 2860 (sh), 1695 (s), 9.75 (s) cm'1; nmr 2.31 (t, / = 7 Hz, CH,CO), 4.00-4.30 (m, 2 H, CHOH), 5.

1. Human hepatic "acid" beta-galactosidase preparations, which had been purified approximately 250-fold, were examined for activities toward 4-methylumbelliferyl beta-galactosylceramide, lactosylceramide, galactosyl-N-acetylgalactosaminyl-[N-acetylneuraminyl]-galactosyl-glucosylceramide(GM1-ganglioside) and galactosyl-N-acetylgalactosaminyl-galactosyl-glucosylceramide (asialo GM1-ganglioside). 2. The enzyme was active toward the synthetic substrate, GM1-ganglioside and asialo GM1-ganglioside but was inactive toward galactosylceramide. Under our assay conditions, optimized for lactosylceramidase II, the preparations were as active toward lactosylceramide as toward GM1-ganglioside or its asialo derivative. The apparent Km values for the three natural substrates were similar. When determined by the assay system of Wehger, D.A., Sattler, M., Clark, C. and McKelvey, H. (1974) Clin. Chim Acta 56, 199-206, lactosylceramide-cleaving activity was 0.2% of that determined by our assay system. This confirmed our previous suggestion that the Wenger assay system determines exclusively the activity of lactosylceramidase I, which is probably identical with galactosylceramide beta-galactosidase. 3. Crude sodium taurocholate was far more effective than pure taurocholate in stimulating hydrolysis of the three glycosphingolipids by the beta-galactosidase. However, crude taurocholate could largely be replaced by smaller amounts of sodium taurodeoxycholate, suggesting that the unique activating capacity of the crude taurocholate might be due to taurodeoxycholate present as the major impurity. 4. Cl- was generally stimulatory for hydrolysis of the natural glycosphingolipids by our enzyme preparation. Effects of additional oleic acid and Triton X-100 were generally minor in either direction. 5. When the enzyme preparation was diluted with water, activity toward the synthetic substrate declined rapidly while those toward the natural substrates were essentially stable. Activity toward the synthetic substrate remained much more stable when the enzyme was diluted with 0.1 M sodium citrate/phosphate buffer, pH 5.0. 6. These observations provide insight into the complex relationship among the human hepatic beta-galactosidases.

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