Sialidases

Rosenberg, Abraham; Schengrund, Cara Lynne

doi:10.1007/978-1-4684-2226-9_10

Cited by 56 publications

(41 citation statements)

References 288 publications

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“…S ialic acids (Sias) are nine-carbon sugars typically found as outermost units on the mammalian cellular glycocalyx and on secreted glycoproteins (1)(2)(3)(4). The most common Sias are Nacetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc).…”

mentioning

confidence: 99%

“…Cellular Neu5Gc is generated by hydroxylation of the sugar nucleotide donor CMP-Neu5Ac to CMP-Neu5Gc, catalyzed by CMP-Neu5Ac hydroxylase (CMAH) (5)(6)(7). Although Neu5Gc is a major Sia in most mammals (including our closest evolutionary relatives, the great apes) (8), it is thought to be absent in healthy humans (1)(2)(3). Indeed, humans generate immune responses against i.v.-administered molecules carrying Neu5Gc, e.g., the ''serum sickness'' reaction to equine antithymocyte globulin therapy (9,10).…”

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confidence: 99%

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Human uptake and incorporation of an immunogenic nonhuman dietary sialic acid

Tangvoranuntakul

Gagneux

Díaz

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

551

586

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Humans are genetically unable to produce the sialic acid N-glycolylneuraminic acid (Neu5Gc), because of a mutation that occurred after our last common ancestor with great apes. Although Neu5Gc is presumed absent from normal humans, small amounts have been claimed to exist in human tumors and fetal meconium. We have generated an antibody with high specificity and avidity for Neu5Gc. Fetal tissues, normal adult tissues, and breast carcinomas from humans showed reactivity to this antibody, primarily within secretory epithelia and blood vessels. The presence of small amounts of Neu5Gc was confirmed by MS. Absent any known alternate pathway for its synthesis, we reasoned that these small amounts of Neu5Gc might originate from exogenous sources. Indeed, human cells fed with Neu5Gc incorporated it into endogenous glycoproteins. When normal human volunteers ingested Neu5Gc, a portion was absorbed and eliminated in urine, and small quantities were incorporated into newly synthesized glycoproteins. Neu5Gc has never been reported in plants or microbes to our knowledge. We found that Neu5Gc is rare in poultry and fish, common in milk products, and enriched in red meats. Furthermore, normal humans have variable amounts of circulating IgA, IgM, and IgG antibodies against Neu5Gc, with the highest levels comparable to those of the previously known anti-␣-galactose xenoreactive antibodies. This finding represents an instance wherein humans absorb and metabolically incorporate a nonhuman dietary component enriched in foods of mammalian origin, even while generating xenoreactive, and potentially autoreactive, antibodies against the same molecule. Potential implications for human diseases are briefly discussed.

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confidence: 99%

mentioning

confidence: 99%

Human uptake and incorporation of an immunogenic nonhuman dietary sialic acid

Tangvoranuntakul

Gagneux

Díaz

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

551

586

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“…Neuraminidase is produced as an extracellular enzyme in culture supernates by Vibrio cholerae and Clostridium perfringens, but is cell-associated in other species, e.g., Klebsiella aerogenes and Pasteurella multocida (see Rosenberg and Schengrund, 1976). Our previous studies confirmed that clostridial neuraminidases are essentially extracellular, although some more enzyme could be released by ultrasonic disintegration of the cells (Fraser and Collee, 1975;Fraser, 1978).…”

Section: Discussionmentioning

confidence: 60%

“…The purity of all cultures was carefully tested by subculture from the test culture. Neuraminidase production has been shown to be inducible in certain species (Nees and Schauer, 1974;Rosenberg and Schengrund, 1976) but we have not been able to identify specific inducing conditions that might explain the variations observed in this study between different media or different batches of the same medium.…”

Section: Discussionmentioning

confidence: 68%

“…ThepH optimum for neuraminidases may vary considerably with different buffer systems and different substrates (Fraser and Smith, 1975;Rosenberg and Schengrund, 1976) but our standard assay with human glycoprotein substrate FVII with acetate buffer at pH 5.1 also gave good results with the B. fragilis enzyme (see the figure). The neuraminidase produced by certain species, e.g., V. cholerae, is calcium dependent but added Ca2+ is not required in our assays for the enzyme produced by clostridia (Fraser, 1978) or Bacteroides species (table 11).…”

Section: Discussionmentioning

confidence: 75%

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Neuraminidase production by Bacteroidaceae

Fraser¹,

Brown²

1981

Journal of Medical Microbiology

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SUMMARY. The production of neuraminidase (EC 3.2.1.18) by 77 strains of Bacteroidaceae was investigated by techniques previously used to study neuraminidase production by clostridia. Conditions for culture and assay of Bacteroides fragilis neuraminidase were characterised. The enzyme is predominantly cell associated; it is not calcium dependent and the pH optimum for its production is c. 4-5.Most neuraminidase-positive Bacteroides strains produced the enzyme well in the test media but a few strains failed to'produce it consistently in one or other of the media. Because of these occasional variations, strains were grown and tested in at least two media before being defined as neuraminidase negative.Within the B. fragilis group of species, B. fragilis, B. vulgatus, B. distasonis, B. ovatus, B. thetaiotaomicron and B. variabilis were neuraminidase positive while B. eggerthii, B. uniformis and B. splanchnicus were negative. Two subspecies of B. melaninogenicus (ss. melaninogenicus and ss. levii) were positive but the other (ss. intermedius) was negative. Strains of B. oralis and B. bivius produced the enzyme while B. ruminicola, B. disiens, B. asaccharolyticus and B. corrodens did not. The microaerophilic B. ochraceus were also positive. None of the Fusobacterium or Leptotrichia species tested produced neuraminidase.Our results for neuraminidase production are consistent for all strains of each species examined and we suggest that tests for neuraminidase production would be a valuable addition to biochemical tests currently used in taxonomic studies of the Bacteroidaceae.

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Glycolipid and Glycoprotein Degradation

Conzelmann

Sandhoff

1987

Advances in Enzymology - And Related Areas of Molecular Biology

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Sialidases

Cited by 56 publications

References 288 publications

Human uptake and incorporation of an immunogenic nonhuman dietary sialic acid

Human uptake and incorporation of an immunogenic nonhuman dietary sialic acid

Neuraminidase production by Bacteroidaceae

Glycolipid and Glycoprotein Degradation

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