pneumoniae produces circulating neuraminidases, which cleave the N-acetylneuraminic acid
and expose the underlying TA.
From over 30 acetylated derivatives of neuraminic acid, N-acetylneuraminic acid
(referred to as sialic acid) is the most common in humans.
2-4) The most frequent Sias are N-acetylneuraminic acid
(Neu5Ac), N-glycolylneuraminic acid (Neu5Gc) and O-acetylated derivatives thereof (most frequently N-acetyl-9-O-acetylneuraminic acid, Neu5,9A[c.
Virtually all mammals produce two types: N-acetylneuraminic acid
(Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc).
These similarities include the facts that both species (1) are chemosensitized by N-acetylneuraminic acid
(NANA) and proline (Thorington and Hessinger, 1988a; Watson and Hessinger, 1989, 1994); (2) yield bimodal dose responses to chemosensitizers (Thorington and Hessinger, 1988a; Watson and Hessinger, 1989); (3) have Type B and Type C CSCCs and the number of Type Bs exceeds the number of Type Cs in 72-h starved anemones (Thorington and Hessinger, 1990, 1996; Watson and Hessinger, 1994); (4) exhibit inhibition of the discharge of Type B CSCCs by L-type calcium channel blockers (Thorington and Hessinger, 1998; Watson and Hessinger, 1994); (5) employ cAMP-mediated chemoreceptor signaling pathways (Watson and Hessinger, 1992; Mire-Thibodeaux and Watson, 1994; Ozacmak et al.
Sialic acids are derived from neuraminic acid whose main derivative is N-acetylneuraminic acid
, which is generally used as a synonym for sialic acid (Ledeen and Yu 1976).
630] bearing the same biantennary carbohydrate structure composed of 2 N-acetylglucosamine (GlcNAc), 3 mannose (Man), 2 GlcNAc, 2 galactose (Gal), and 2 N-acetylneuraminic acid
(NeuNAc; sialic acid; see structure in Table 2).
An example is a concise synthesis of N-acetylneuraminic acid
(12) from N-acetylmannosamine (11) as outlined in Scheme 2.
There are eight essential saccharides: mannose, glucose, galactose, xylose, fucose, N-acetylglucosamine, N-acetylgalactosamine and N-acetylneuraminic acid
Since many years, it is known that ML I binds to galactose, but current investigations propose a specific-binding site for ML I consisting of N-acetylglucosamin, galactose and terminal N-acetylneuraminic acid
3) Nonstandard abbreviations: SSD, sialic acid storage disease; ISSD, infantile sialic acid storage disease; NANA, N-acetylneuraminic acid
(free sialic acid); HPAE-PAD, high-performance anion-exchange pulsed amperometric detection; tMS, tandem mass spectrometry; KDN, 2-keto-3-deoxy-D-glycero-D-galactonononic acid; IS, internal standard; ESI, electrospray ionization; MRM, multiple reaction monitoring; ERNDIM, European Research Network for Evaluation and Improvement of Screening Diagnosis and Treatment of Inherited Disorders of Metabolism; and LOD, limit(s) of detection.
, NANA) and for certain amino compounds (e.