AdoHcyase is a highly conserved protein[4] with about 430 to 470 amino acids. The family contains a glycine-rich region in the central part of AdoHcyase; a region thought to be involved in NAD-binding. AdoHcyase binds one NAD+ cofactor per subunit. This protein may use the morpheein model of allosteric regulation.[5]
Overall hydrolysis begins with dehydrogenative oxidation of the 3'-OH of the ribose by NAD+ (forming NADH). The resulting ketone is α-deprotonated to the enol before elimination of the homocysteine thiolate. Water then adds to the a,b-unsaturated ketone, before reduction of the resultant ketone by NADH.
AdoHcyase is encoded by the AHCY gene in humans,[6][7] which is believed to have a prognostic role in neuroblastoma.[8] AdoHcyase is significantly associated with adenosine deaminase deficiency, which classically manifests in severe combine immunodeficiency (SCID). Accumulated adenosine derivatives, dATPs, irreversibly bind to and inhibit AdoHcyase, promoting the buildup of S-adenosyl-L-homocystine (due to equilibrium constant favors S-adenosyl-L-homocystine), a potent inhibitor of methyl transfer reactions.[9]
^Hu Y, Komoto J, Huang Y, et al. (June 1999). "Crystal structure of S-adenosylhomocysteine hydrolase from rat liver". Biochemistry. 38 (26): 8323–33. doi:10.1021/bi990332k. PMID10387078.
Well, that’s interesting to know that Psilotum nudum are known as whisk ferns. Psilotum nudum is the commoner species of the two. While the P. flaccidum is a rare species and is found in the tropical islands. Both the species are usually epiphytic in habit and grow upon tree ferns. These species may also be terrestrial and grow in humus or in the crevices of the rocks.
View the detailed Guide of Psilotum nudum: Detailed Study Of Psilotum Nudum (Whisk Fern), Classification, Anatomy, Reproduction
Well, that’s interesting to know that Psilotum nudum are known as whisk ferns. Psilotum nudum is the commoner species of the two. While the P. flaccidum is a rare species and is found in the tropical islands. Both the species are usually epiphytic in habit and grow upon tree ferns. These species may also be terrestrial and grow in humus or in the crevices of the rocks.
View the detailed Guide of Psilotum nudum: Detailed Study Of Psilotum Nudum (Whisk Fern), Classification, Anatomy, Reproduction