The Blood Group problem!!!!
Richard L. Hall
rhall at webmail.uvi.edu
Mon Jan 15 09:25:55 EST 2001
Actually, I just finished my coffee and realized that the A and B
genes may not be "glycosylating" enzymes but instead a enzymes
producing something like UDP-galactose, UDP-N-acetylgalactosamine
substrates for the phosphotransferases used in producing
oligosaccharides (and glycolipids) in the golgi apparatus.
The gist of my comments are probably correct, it is in the details
where we frequently founder.
>Wrong! Everybody has the "O-gene."
>Genes are expressed as polypeptides or proteins. The A and B
>antigens are NOT proteins but rather glycolipids found on the
>membranes of most human cells. The proteins produced by "A and B
>genes" are enzymes that catalyze the addition of specific sugars
>(either N-acetylgalactosamine or D-galactose) to a glycolipid
>consisting of L-fucose: D-galactose: N-acetylglucosamine:
>D-galactose: N-acetylgalactosamine:lipid. The five sugar glycolipid
>is sometimes called the 'H-antigen" although it is actually
>non-antigenic. The A or B antigens are formed by the addition of
>either N-acetylgalactosamine or D-galactose to the H-antigen.
>The so called "O gene" produces the glycosylating enzyme (or
>enzymes) producing the "H-antigen." There are "A-genes, B-genes,
>and "O genes" as well as an A-antigen, a B-antigen, and a
>"H-antigen" and they are apparently inherited in a Mendelian fashion.
>>In human blood groups the AB blood type has a gene for type A blood inherited
>>from one parent and a gene B inherited by the other parent, so you see there
>>are no O genes in blood group AB therefore a baby with blood type O can not
>Richard L. Hall, Ph.D.
>Comparative Animal Physiologist
>University of the Virgin Islands
>2 John Brewers Bay
>St. Thomas, U.S.V.I. 00802
>rhall at uvi.edu
>"Live life on the edge...the view is always better" rlh
Richard L. Hall, Ph.D.
Comparative Animal Physiologist
University of the Virgin Islands
2 John Brewers Bay
St. Thomas, U.S.V.I. 00802
rhall at uvi.edu
"Live life on the edge...the view is always better" rlh
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