Acetylneuraminic acid is another name for sialic acid, one of a
group of amino carbohydrates, which is a component of glycoproteins
and mucoproteins.
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cow's milk, cheese, pork, beef, salmon, tuna,
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It helps to break it down:
a-sial-o-glyc-o-protein
"o" is just a combining phoneme; ignoring those, we're left with a (not) sial (sialic acid, a type of sugar acid that occurs at the end of saccharide (sugar) chains in biological systems) glyc (an oligo (several) saccharide chain) protein (I hope you know what this means).
Putting them back together we get "a protein bonded to a chain of several sugars that has had its terminal sialic acid residues removed".
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Spermatozoa has sialic acid coat wich hides the antiden,,, plus
the uterine endometrium is immunosuppresive