Blood-group enzymatic synthesis

SCHEME 3.30 Enzymatic synthesis of the blood group B antigen tetrasaccharide. UDP, uridine diphosphate. 

Basu, M., Chien, J-L Basu, S. (1974) Enzymatic Synthesis of Blood Group H Related Glycosphingolipid , Federation Proceedings of the Federation of American Societies for Experimental Biology, 33, 1225... 

TRH is synthesized in a wide area of the hypothalamus and is controlled by a non-ribosomal enzyme,TRH-synthetase [31]. It is stored in the median eminence and secreted when required into the hypophysial portal vessels [32]. TRH binds to membrane receptors on the pituitary cells [33] and increases both the synthesis [34] and the release [35] of TSH. Since TRH has been shown to activate adenyl cyclase [36], this action is believed to be mediated via 3, 5 -cyclic adenosine monophosphate (cyclic AMP). The half-life of TRH in vivo is approximately 4 min. It is destroyed in the blood by enzymatic (TRH-degrading enzyme) cleavage of the amide group [37] and excreted via the kidney [32]. The TRH-degrading enzyme is present both in peripheral and hypophysial portal blood of rats but TRH is more rapidly destroyed in the peripheral blood. On the basis of these results, it has been suggested that the portal blood either contains only a low concentration of enzyme or that it contains high concentrations of unidentified substances which act as competitive inhibitors of or substrates for the enzyme [38]. 

Enzymatic Synthesis of the Primary Chains of Blood Group i-Type... 

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