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. 1973 May;133(1):81–87. doi: 10.1042/bj1330081

The effect of methanol and dioxan on the rates of the β-galactosidase-catalysed hydrolyses of some β-d-galactopyranosides: rate-limiting degalactosylation. The pH-dependence of galactosylation and degalactosylation

Michael L Sinnott 1,2, Odile M Viratelle 1,2
PMCID: PMC1177672  PMID: 4721624

Abstract

1. The effect of methanol on the β-galactosidase-catalysed hydrolysis of some nitrophenyl β-d-galactopyranosides has been studied under steady-state conditions. 2. The initial fractional rate of increase of kcat. as a function of methanol concentration with 2,4- and 3,5-dinitrophenyl β-d-galactopyranosides, but not with the other substrates studied, indicated that degalactosylation of the enzyme was rate-limiting. 3. The decrease in kcat. at high methanol concentrations for these substrates is considered to arise from causes other than galactosylation becoming rate-limiting. 4. Both galactosylation and degalactosylation of the enzyme require protonation of a group of pKa approx. 9.

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Selected References

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

  1. CONCHIE J., LEVVY G. A., MARSH C. A. Methyl and phenyl glycosides of the common sugars. Adv Carbohydr Chem. 1957;12:157–187. doi: 10.1016/s0096-5332(08)60208-8. [DOI] [PubMed] [Google Scholar]
  2. Halford S. E. Escherichia coli alkaline phosphatase. An analysis of transient kinetics. Biochem J. 1971 Nov;125(1):319–327. doi: 10.1042/bj1250319. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Jones B. M., Kemp R. B. Aggregation and electrophoretic mobility studies on dissociated cells. II. Effects of ADP and ATP. Exp Cell Res. 1970 Dec;63(2):301–308. doi: 10.1016/0014-4827(70)90217-x. [DOI] [PubMed] [Google Scholar]
  4. Shifrin S., Hunn G. Effect of alcohols on the enzymatic activity and subunit association of beta-galactosidase. Arch Biochem Biophys. 1969 Mar;130(1):530–535. doi: 10.1016/0003-9861(69)90066-6. [DOI] [PubMed] [Google Scholar]
  5. Sinnott M. L., Souchard I. J. The mechanism of action of beta-galactosidase. Effect of aglycone nature and -deuterium substitution on the hydrolysis of aryl galactosides. Biochem J. 1973 May;133(1):89–98. doi: 10.1042/bj1330089. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Stokes T. M., Wilson I. B. A common intermediate in the hydrolysis of -galactosides by -galactosidase from Escherichia coli. Biochemistry. 1972 Mar 14;11(6):1061–1064. doi: 10.1021/bi00756a018. [DOI] [PubMed] [Google Scholar]
  7. Tenu J. P., Viratelle O. M., Garnier J., Yon J. pH dependence of the activity of beta-galactosidase from Escherichia coli. Eur J Biochem. 1971 Jun 11;20(3):363–370. doi: 10.1111/j.1432-1033.1971.tb01402.x. [DOI] [PubMed] [Google Scholar]
  8. Viratelle O., Tenu J. P., Garnier J., Yon J. A preliminary study of the nucleophilic competition in beta-galactosidase catalyzed reactions. Biochem Biophys Res Commun. 1969 Dec 4;37(6):1036–1041. doi: 10.1016/0006-291x(69)90236-8. [DOI] [PubMed] [Google Scholar]
  9. WALLENFELS K., KURZ G. [On the specificity of galactose dehydrogenase from Pseudomonas saccharophila and its use as an analytical aid]. Biochem Z. 1962;335:559–573. [PubMed] [Google Scholar]
  10. WALLENFELS K., MALHOTRA O. P. Galactosidases. Adv Carbohydr Chem. 1961;16:239–298. doi: 10.1016/s0096-5332(08)60264-7. [DOI] [PubMed] [Google Scholar]

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