Skip to main content
Biochemical Journal logoLink to Biochemical Journal
. 1971 Oct;124(4):701–711. doi: 10.1042/bj1240701

The substrate specificity of acid α-glucosidase from rabbit muscle

T N Palmer 1,*
PMCID: PMC1177247  PMID: 5131728

Abstract

1. Acid α-glucosidase was purified 3500-fold from rabbit muscle. 2. The enzyme was activated by cations, the degree of activation varying with the substrate. Enzyme action on glycogen was most strongly activated and activation was apparently of a non-competitive type. With rabbit liver glycogen as substrate, the relative Vmax. increased 15-fold, accompanied by an increase in Km from 8.3 to 68.6mm-chain end over the cation range 2–200mm-Na+ at pH4.5. Action on maltose was only moderately activated (1.3-fold, non-competitively) and action on maltotriose was marginally and competitively inhibited. 3. The pH optimum at 2mm-Na+ was 4.5 (maltose) and 5.1 (glycogen). Cation activation of enzyme action on glycogen was markedly pH-dependent. At 200mm-Na+, the pH optimum was 4.8 and activity was maximally stimulated in the range pH4.5–3.3. 4. Glucosidase action on maltosaccharides was associated with pronounced substrate inhibition at concentrations exceeding 5mm. Of the maltosaccharides tested, the enzyme showed a preference for p-nitrophenyl α-maltoside (Km 1.2mm) and maltotriose (Km 1.8mm). The extrapolated Km for enzyme action on maltose was 3.7mm. 5. The macromolecular polysaccharide substrate glycogen differed from linear maltosaccharide substrates in the kinetics of its interaction with the enzyme. Activity was markedly dependent on pH, cation concentration and polysaccharide structure. There was no substrate inhibition. 6. The enzyme exhibited constitutive α-1,6-glucanohydrolase activity. The Km for panose was 20mm. 7. The enzyme catalysed the total conversion of glycogen into glucose. The hydrolysis of α-1,6-linkages was apparently rate-limiting during the hydrolysis of glycogen. 8. Enzyme action on glycogen and maltose released the α-anomer of d-glucose. 9. The results are discussed in terms of the physiological role of acid α-glucosidase in lysosomal glycogen catabolism.

Full text

PDF
701

Selected References

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

  1. Auricchio F., Bruni C. B. Purification of an acid alpha-glucosidase by dextran-gel filtration. Biochem J. 1967 Oct;105(1):35–38. doi: 10.1042/bj1050035. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Auricchio F., Bruni C. B., Sica V. Further purification and characterization of the acid alpha-glucosidase. Biochem J. 1968 Jun;108(2):161–167. doi: 10.1042/bj1080161. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Bruni C. B., Auricchio F., Covelli I. Acid alpha-D-glucosidase glucohydrolase from cattle liver. J Biol Chem. 1969 Sep 10;244(17):4735–4742. [PubMed] [Google Scholar]
  4. Carter J. H., Lee E. Y. An enzymic method for determination of the average chain lengths of glycogens and amylopectins. Anal Biochem. 1971 Feb;39(2):373–386. doi: 10.1016/0003-2697(71)90427-1. [DOI] [PubMed] [Google Scholar]
  5. DAVIS B. J. DISC ELECTROPHORESIS. II. METHOD AND APPLICATION TO HUMAN SERUM PROTEINS. Ann N Y Acad Sci. 1964 Dec 28;121:404–427. doi: 10.1111/j.1749-6632.1964.tb14213.x. [DOI] [PubMed] [Google Scholar]
  6. DIXON M. The determination of enzyme inhibitor constants. Biochem J. 1953 Aug;55(1):170–171. doi: 10.1042/bj0550170. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Fujimori K., Hizukuri S., Nikuni Z. Studies on acid alpha-1,4-glucosidase from bovine spleen. Biochem Biophys Res Commun. 1968 Sep 6;32(5):811–816. doi: 10.1016/0006-291x(68)90313-6. [DOI] [PubMed] [Google Scholar]
  8. Jeffrey P. L., Brown D. H., Brown B. I. Studies of lysosomal alpha-glucosidase. I. Purification and properties of the rat liver enzyme. Biochemistry. 1970 Mar 17;9(6):1403–1415. doi: 10.1021/bi00808a015. [DOI] [PubMed] [Google Scholar]
  9. Jeffrey P. L., Brown D. H., Brown B. I. Studies of lysosomal alpha-glucosidase. II. Kinetics of action of the rat liver enzyme. Biochemistry. 1970 Mar 17;9(6):1416–1422. doi: 10.1021/bi00808a016. [DOI] [PubMed] [Google Scholar]
  10. 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]
  11. LUKOMSKAYA I. S. The synthesis of oligosaccharides with different types of linkage in animal tissues. Enzymologia. 1962 Aug 15;24:327–337. [PubMed] [Google Scholar]
  12. Lee E. Y., Whelan W. J. Enzymic methods for the microdetermination of glycogen and amylopectin, and their unit-chain lengths. Arch Biochem Biophys. 1966 Sep 26;116(1):162–167. doi: 10.1016/0003-9861(66)90024-5. [DOI] [PubMed] [Google Scholar]
  13. Lloyd J. B., Whelan W. J. An improved method for enzymic determination of glucose in the presence of maltose. Anal Biochem. 1969 Sep;30(3):467–470. doi: 10.1016/0003-2697(69)90143-2. [DOI] [PubMed] [Google Scholar]
  14. Marshall J. J., Whelan W. J. Incomplete conversion of glycogen and starch by crystalline amyloglucosidase and its importance in the determination of amylaceous polymers. FEBS Lett. 1970 Jul 29;9(2):85–88. doi: 10.1016/0014-5793(70)80319-2. [DOI] [PubMed] [Google Scholar]
  15. Palmer T. N. The maltase, glucoamylase and transglucosylase activities of acid -glucosidase from rabbit muscle. Biochem J. 1971 Oct;124(4):713–724. doi: 10.1042/bj1240713. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. TORRES H. N., OLAVARRIA J. M. LIVER ALPHA-GLUCOSIDASES. J Biol Chem. 1964 Aug;239:2427–2434. [PubMed] [Google Scholar]
  17. TREVELYAN W. E., PROCTER D. P., HARRISON J. S. Detection of sugars on paper chromatograms. Nature. 1950 Sep 9;166(4219):444–445. doi: 10.1038/166444b0. [DOI] [PubMed] [Google Scholar]
  18. WALKER G. J., WHELAN W. J. The mechanism of carbohydrase action. 8. Structures of the muscle-phosphorylase limit dextrins of glycogen and amylopectin. Biochem J. 1960 Aug;76:264–268. doi: 10.1042/bj0760264. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Biochemical Journal are provided here courtesy of The Biochemical Society

RESOURCES