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Home / Equine Research Bank / Glycoconj J / Indications for the enzymatic synthesis of 9-O-lactoyl-N-ace...
Glycoconjugate journal1993; 10(1); 116-119; doi: 10.1007/BF00731195

Indications for the enzymatic synthesis of 9-O-lactoyl-N-acetylneuraminic acid in equine liver.

Abstract: Fractionation of horse liver homogenate by centrifugation into heavy membranes at 10,000 x g, microsomal fraction at 105,000 x g, and the supernatant revealed sialate 9-O-lactoyltransferase activity only in the latter fraction. For the enzyme assay, the various fractions were incubated with 14C labelled CMP-N-acetylneuraminic acid, N-acetylneuramimic acid and glycoconjugate-bound N-acetylneuramimic acid. Lactoylation was identified in three different TLC systems after acid hydrolysis and purification of the sialic acids in the incubation mixtures. Enzyme activity was found only in the supernatant fraction. Glycoconjugate-bound N-acetylneuramimic acid was the best substrate tested, although some lactoylation was also found when using CMP-N-acetylneuraminic acid.
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Publication Date: 1993-02-01 PubMed ID: 8358222DOI: 10.1007/BF00731195Google Scholar: Lookup
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  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

This study investigates the existence and action of a specific enzyme in horse liver that synthesizes a molecule called 9-O-lactoyl-N-acetylneuraminic acid. The enzyme, identified as ‘sialate 9-O-lactoyltransferase’, was found predominantly in the supernatant fraction after centrifugation of horse liver cell components.

Methodology and Substance Fractionation

  • The researchers took a homogenate (a mixture with evenly distributed particles) of horse liver and fractionated or divided this into three parts by centrifugation (a process often used in labs to separate substances of different densities). These parts consisted of heavy membranes at 10,000 x g, a microsomal fraction at 105,000 x g, and the supernatant, or the liquid fraction that is left after all the solids have been settled out by centrifugation.
  • The objective was to locate where the enzyme sialate 9-O-lactoyltransferase was most active. This enzyme is responsible for the synthesis of 9-O-lactoyl-N-acetylneuraminic acid, a specific type of molecule.

Enzyme Assay and Identification of Lactoylation

  • To measure enzyme activity, the different fractions were mixed with a particular compound known as CMP-N-acetylneuraminic acid, marked with a radioactive C-14 label. Mixing N-acetylneuramimic acid and glycoconjugate-bound N-acetylneuramimic acid also occurred.
  • The process of lactoylation, or the addition of a lactoyl group (a specific atomic or molecular arrangement), was identified using three different thin layer chromatography (TLC) systems. TLC is a technique often used to separate and identify compounds present in a given substance.
  • This process of identification ensued after acid hydrolysis (a method used to break down chemical compounds) and the purification of sialic acids in the incubation mixtures.

Results and Conclusion

  • The results indicated that enzyme activity for sialate 9-O-lactoyltransferase was found only in the supernatant fraction. It suggests that this enzyme is more abundant or functional in this fraction of the horse liver homogenate.
  • Glycoconjugate-bound N-acetylneuramimic acid emerged as the most effective substrate, even though some lactoylation was observed with CMP-N-acetylneuraminic acid. A substrate is a molecule upon which an enzyme acts. This result implicates glycoconjugate-bound N-acetylneuramimic acid as an ideal molecule for this particular enzyme to act upon for the synthesis of 9-O-lactoyl-N-acetylneuraminic acid in the horse liver.

Cite This Article

APA
Kleineidam RG, Hofmann O, Reuter G, Schauer R. (1993). Indications for the enzymatic synthesis of 9-O-lactoyl-N-acetylneuraminic acid in equine liver. Glycoconj J, 10(1), 116-119. https://doi.org/10.1007/BF00731195

Publication

Glycoconjugate journal
ISSN: 0282-0080
NlmUniqueID: 8603310
Country: United States
Language: English
Volume: 10
Issue: 1
Pages: 116-119

Researcher Affiliations

Kleineidam, R G
  • Biochemisches Institut, Christian-Albrechts-Universität, Kiel, Germany.
Hofmann, O
    Reuter, G
      Schauer, R

        MeSH Terms

        • Acyltransferases / metabolism
        • Animals
        • Horses / metabolism
        • Microsomes, Liver / metabolism
        • Sialic Acids / analysis
        • Sialic Acids / biosynthesis

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        Citations

        This article has been cited 2 times.
        1. Schauer R, Kamerling JP. Exploration of the Sialic Acid World. Adv Carbohydr Chem Biochem 2018;75:1-213.
          doi: 10.1016/bs.accb.2018.09.001pubmed: 30509400google scholar: lookup
        2. Schauer R. Achievements and challenges of sialic acid research. Glycoconj J 2000 Jul-Sep;17(7-9):485-99.
          doi: 10.1023/a:1011062223612pubmed: 11421344google scholar: lookup
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