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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

        References

        This article includes 15 references
        1. Schauer R. Analysis of sialic acids.. Methods Enzymol 1987;138:132-61.
          pubmed: 3600319doi: 10.1016/0076-6879(87)38012-7google scholar: lookup
        2. Manzi AE, Dell A, Azadi P, Varki A. Studies of naturally occurring modifications of sialic acids by fast-atom bombardment-mass spectrometry. Analysis of positional isomers by periodate cleavage.. J Biol Chem 1990 May 15;265(14):8094-107.
          pubmed: 2159468
        3. Muchmore EA, Varki NM, Fukuda M, Varki A. Developmental regulation of sialic acid modifications in rat and human colon.. FASEB J 1987 Sep;1(3):229-35.
          pubmed: 3623000doi: 10.1096/fasebj.1.3.3623000google scholar: lookup
        4. Haverkamp J, Schauer R, Wember M. Neuraminic acid derivatives newly discovered in humans: N-acetyl-9-O-L-lactoylneuraminic acid, N,9-O-Diacetylneuraminic acid and N-acetyl-2,3-dehydro-2-deoxyneuraminic acid.. Hoppe Seylers Z Physiol Chem 1976 Dec;357(12):1699-705.
          pubmed: 1017796doi: 10.1515/bchm2.1976.357.2.1699google scholar: lookup
        5. CRUMPTON MJ. Identification of amino sugars.. Biochem J 1959 Jul;72(3):479-86.
          pubmed: 13813097doi: 10.1042/bj0720479google scholar: lookup
        6. Schauer R. Chemistry, metabolism, and biological functions of sialic acids.. Adv Carbohydr Chem Biochem 1982;40:131-234.
          pubmed: 6762816doi: 10.1016/s0065-2318(08)60109-2google scholar: lookup
        7. Veh RW, Michalski JC, Corfield AP, Sander-Wewer M, Gies D, Schauer R. New chromatographic system for the rapid analysis and preparation of colostrum sialyloligosaccharides.. J Chromatogr 1981 Aug 7;212(3):313-22.
          pubmed: 7263800doi: 10.1016/s0021-9673(01)84044-9google scholar: lookup
        8. Varki A, Diaz S. The release and purification of sialic acids from glycoconjugates: methods to minimize the loss and migration of O-acetyl groups.. Anal Biochem 1984 Feb;137(1):236-47.
          pubmed: 6731802doi: 10.1016/0003-2697(84)90377-4google scholar: lookup
        9. Sambasivam H, Murray RK. A comparison of acetylation in vitro of microsomal, homogenate, and Golgi fractions of rat liver.. Biochem Cell Biol 1988 Oct;66(10):1152-61.
          pubmed: 3145755doi: 10.1139/o88-132google scholar: lookup
        10. Schauer R, Reuter G, Stoll S. Sialate O-acetylesterases: key enzymes in sialic acid catabolism.. Biochimie 1988 Nov;70(11):1511-9.
          pubmed: 3149520doi: 10.1016/0300-9084(88)90288-xgoogle scholar: lookup
        11. Schauer R, Reuter G, Stoll S, Shukla AK. Partial purification and characterization of sialate O-acetylesterase from bovine brain.. J Biochem 1989 Jul;106(1):143-50.
          pubmed: 2777745doi: 10.1093/oxfordjournals.jbchem.a122804google scholar: lookup
        12. Schauer R, Haverkamp J, Wember M, Kamerling JP, Vliegenthart JF. N-acetyl-9-O-L-lactylneuraminic acid, a new acylneuraminic acid from bovine submandibular gland.. Eur J Biochem 1976 Feb 16;62(2):237-42.
          pubmed: 1253789doi: 10.1111/j.1432-1033.1976.tb10153.xgoogle scholar: lookup
        13. Pozsgay V, Jennings H, Kasper DL. 4,8-anhydro-N-acetylneuraminic acid. Isolation from edible bird's nest and structure determination.. Eur J Biochem 1987 Jan 15;162(2):445-50.
          pubmed: 3803396doi: 10.1111/j.1432-1033.1987.tb10622.xgoogle scholar: lookup
        14. Reuter G, Pfeil R, Kamerling JP, Vliegenthart JF, Schauer R. Identification by gas-liquid chromatography-mass spectrometry of 4-O-acetyl-9-O-lactyl-N-acetyl-neuraminic acid, a new sialic acid from horse submandibular gland.. Biochim Biophys Acta 1980 Jun 19;630(2):306-10.
          pubmed: 7388057doi: 10.1016/0304-4165(80)90435-3google scholar: lookup
        15. Varki A, Diaz S. The transport and utilization of acetyl coenzyme A by rat liver Golgi vesicles. O-acetylated sialic acids are a major product.. J Biol Chem 1985 Jun 10;260(11):6600-8.
          pubmed: 3997840

        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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