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. 1969 Apr;48(4):716–728. doi: 10.1172/JCI106029

Intestinal β-galactosidases

I. Separation and characterization of three enzymes in normal human intestine

Gary M Gray 1, Nilda A Santiago 1
PMCID: PMC322276  PMID: 5774109

Abstract

Previous studies based on work in the rat and preliminary experiments with human intestine have suggested that two β-galactosidases are present in small intestine, and it is believed that only one of these enzymes is a lactase important for the digestion of dietary lactose. The high prevalence of intestinal lactase deficiency in man prompted more complete study of these enzymes.

Human intestinal β-galactosidases were studied by gel filtration on Sephadex G-200 and Biogel P-300 as well as by density gradient ultracentrifugation. Gel filtration produced partial separation into three peaks of enzyme activity, but much activity against synthetic substrates was lost. Only the trailing peak with specificity for synthetic β-galactosides was completely separated from the other enzymes. Thus gel filtration was not a suitable preparative procedure for biochemical characterization.

Density gradients separated the enzymes more completely, and they were designated according to their sedimentation rates and further characterized. Enzyme I has a molecular weight of 280,000, pH optimum of 6.0, and specificity for lactose of at least five times that for cellobiose or synthetic substrates. A second lactase, enzyme II, possesses slightly greater activity against lactose than for some synthetic substrates and is incapable of splitting cellobiose. Further, it has a lower pH optimum (4.5) and is present in two molecular species (molecular weights 156,000 and 660,000). Enzyme III shows specificity only for synthetic β-galactosides but has a pH activity curve identical with enzyme I and a molecular weight of 80,000. Whereas human liver and kidney contain a β-galactosidase with the same biochemical characteristics as intestinal enzyme II, enzymes I and III appear to be peculiar to intestine, and enzyme I most probably represents the lactase of importance in the mucosal digestion of dietary lactose. The following paper considers this further in terms of the biochemical change in intestinal lactase deficiency.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. AURICCHIO S., RUBINO A., TOSI R., SEMENZA G., LANDOLT M., KISTLER H., PRADER A. DISACCHARIDASE ACTIVITIES IN HUMAN INTESTINAL MUCOSA. Enzymol Biol Clin (Basel) 1963;74:193–208. doi: 10.1159/000458059. [DOI] [PubMed] [Google Scholar]
  2. Andrews P. Estimation of the molecular weights of proteins by Sephadex gel-filtration. Biochem J. 1964 May;91(2):222–233. doi: 10.1042/bj0910222. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Bayless T. M., Rosensweig N. S. A racial difference in incidence of lactase deficiency. A survey of milk intolerance and lactase deficiency in healthy adult males. JAMA. 1966 Sep 19;197(12):968–972. [PubMed] [Google Scholar]
  4. COHEN R. B., TSOU K-C, RUTENBURG S. H., SELIGMAN A. M. The colorimetric estimation and histochemical demonstration of beta-d-galactosidase. J Biol Chem. 1952 Mar;195(1):239–249. [PubMed] [Google Scholar]
  5. Cook G. C., Kajubi S. K. Tribal incidence of lactase deficiency in Uganda. Lancet. 1966 Apr 2;1(7440):725–729. doi: 10.1016/s0140-6736(66)90888-9. [DOI] [PubMed] [Google Scholar]
  6. Cook G. C., Lee F. D. The jejunum after kwashiorkor. Lancet. 1966 Dec 10;2(7476):1263–1267. doi: 10.1016/s0140-6736(66)91686-2. [DOI] [PubMed] [Google Scholar]
  7. DAHLQVIST A., BULL B., GUSTAFSSON B. E. RAT INTESTINAL 6-BROMO-2-NAPHTHYL GLYCOSIDASE AND DISACCHARIDASE ACTIVITIES. I. ENZYMIC PROPERTIES AND DISTRIBUTION IN THE DIGESTIVE TRACT OF CONVENTIONAL AND GERM-FREE ANIMALS. Arch Biochem Biophys. 1965 Jan;109:150–158. doi: 10.1016/0003-9861(65)90300-0. [DOI] [PubMed] [Google Scholar]
  8. DAHLQVIST A., BULL B., THOMSON D. L. RAT INTESTINAL 6-BROMO-2-NAPHTHYL GLYCOSIDASE AND DISACCHARIDASE ACTIVITIES. II. SOLUBILIZATION AND SEPARATION OF THE SMALL-INTESTINAL ENZYMES. Arch Biochem Biophys. 1965 Jan;109:159–167. doi: 10.1016/0003-9861(65)90301-2. [DOI] [PubMed] [Google Scholar]
  9. DOELL R. G., KRETCHMER N. Studies of small intestine during development. I. Distribution and activity of beta-galactosidase. Biochim Biophys Acta. 1962 Aug 13;62:353–362. doi: 10.1016/0006-3002(62)90097-5. [DOI] [PubMed] [Google Scholar]
  10. Eichholz A. Studies on the organization of the brush border in intestinal epithelial cells. V. Subfractionation of enzymatic activities of the microvillus membrane. Biochim Biophys Acta. 1968 Aug;163(1):101–107. doi: 10.1016/0005-2736(68)90037-0. [DOI] [PubMed] [Google Scholar]
  11. Gray G. M., Ingelfinger F. J. Intestinal absorption of sucrose in man: interrelation of hydrolysis and monosaccharide product absorption. J Clin Invest. 1966 Mar;45(3):388–398. doi: 10.1172/JCI105354. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Gray G. M. Malabsorption of carbohydrate. Fed Proc. 1967 Sep;26(5):1415–1419. [PubMed] [Google Scholar]
  13. Gray G. M., Santiago N. A. Disaccharide absorption in normal and diseased human intestine. Gastroenterology. 1966 Oct;51(4):489–498. [PubMed] [Google Scholar]
  14. Gray G. M., Walter W. M., Jr, Colver E. H. Persistent deficiency of intestinal lactase in apparently cured tropical sprue. Gastroenterology. 1968 Apr;54(4):552–558. [PubMed] [Google Scholar]
  15. Hsia D. Y., Makler M., Semnza G., Prader A. Beta-galactosidase activity in human intestinal lactases. Biochim Biophys Acta. 1966 Feb 14;113(2):390–393. doi: 10.1016/s0926-6593(66)80077-2. [DOI] [PubMed] [Google Scholar]
  16. Huang S. S., Bayless T. M. Milk and lactose intolerance in healthy Orientals. Science. 1968 Apr 5;160(3823):83–84. doi: 10.1126/science.160.3823.83-a. [DOI] [PubMed] [Google Scholar]
  17. Johnson C. F. Disaccharidase: localization in hamster intestine brush borders. Science. 1967 Mar 31;155(3770):1670–1672. doi: 10.1126/science.155.3770.1670. [DOI] [PubMed] [Google Scholar]
  18. Kolínská J., Semenza G. Studies on intestinal sucrase and on intestinal sugar transport. V. Isolation and properties of sucrase-isomaltase from rabbit small intestine. Biochim Biophys Acta. 1967 Sep 12;146(1):181–195. doi: 10.1016/0005-2744(67)90085-x. [DOI] [PubMed] [Google Scholar]
  19. LEDERBERG J. The beta-d-galactosidase of Escherichia coli, strain K-12. J Bacteriol. 1950 Oct;60(4):381–392. doi: 10.1128/jb.60.4.381-392.1950. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
  21. London D. R., Cuatrecasas P., Birge S. J., Jr, Segal S. Metabolism of lactose by intestinal mucosa from normal and lactase-deficient subjects. Br Med J. 1967 Mar 4;1(5539):524–526. doi: 10.1136/bmj.1.5539.524. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. MARTIN R. G., AMES B. N. A method for determining the sedimentation behavior of enzymes: application to protein mixtures. J Biol Chem. 1961 May;236:1372–1379. [PubMed] [Google Scholar]
  23. Messer M., Kerry K. R. Intestinal digestion of maltotriose in man. Biochim Biophys Acta. 1967 Mar 15;132(2):432–443. doi: 10.1016/0005-2744(67)90162-3. [DOI] [PubMed] [Google Scholar]
  24. Okada S., O'Brien J. S. Generalized gangliosidosis: beta-galactosidase deficiency. Science. 1968 May 31;160(3831):1002–1004. doi: 10.1126/science.160.3831.1002. [DOI] [PubMed] [Google Scholar]
  25. PLOTKIN G. R., ISSELBACHER K. J. SECONDARY DISACCHARIDASE DEFICIENCY IN ADULT CELIAC DISEASE (NONTROPICAL SPRUE) AND OTHER MALABSORPTION STATES. N Engl J Med. 1964 Nov 12;271:1033–1037. doi: 10.1056/NEJM196411122712003. [DOI] [PubMed] [Google Scholar]
  26. SEMENZA G., AURICCHIO S., RUBINO A. MULTIPLICITY OF HUMAN INTESTINAL DISACCHARIDASES. I. CHROMATOGRAPHIC SEPARATION OF MALTASES AND OF TWO LACTASES. Biochim Biophys Acta. 1965 Mar 22;96:487–497. doi: 10.1016/0005-2787(65)90565-4. [DOI] [PubMed] [Google Scholar]

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