Kinetic properties of the common electrophoretic variants of human S-adenosylhomocysteine hydrolase (AHCY): the effect of four nucleoside analogue inhibitors.
Red blood cell S-adenosylhomocysteine hydrolase (AHCY) from individuals of 1, 2-1 and 3-1 phenotypes was partially purified and Km and Vmax determined in the absence and in the presence of the following inhibitors: 3-deaza-adenosine (DZA), 3-deaza-aristeromycin (DZAry), 2-chloro adenosine (2-Cl-ado) and purine riboside (or nebularine). The three phenotypes 1, 2-1, 3-1 showed similar Km (32.58, 39.22 and 34.84 microM respectively), but the ratio Km/Vmax was statistically different. DZA and DZAry appeared to be strong competitive inhibitors. The AHCY 1 phenotype was more resistant to their action, while the 3-1 variant was more sensitive. 2-Cl-ado and purine riboside were weaker inhibitors; the type of inhibition varied among the three phenotypes, but, again, the AHCY 1 phenotype was less sensitive than the other two.
Corbo
R M
RM
Department of Genetics and Molecular Biology, University La Sapienza, Rome, Italy.
Ingianna
R
R
Scacchi
R
R
Bozzi
A
A
D015762:2-Chloroadenosine / Q000494:pharmacology*; D000241:Adenosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D043383:Adenosylhomocysteinase; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004912:Erythrocytes / Q000201:enzymology; D006801:Humans; D006867:Hydrolases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D007536:Isomerism; D007700:Kinetics; D011684:Purine Nucleosides / Q000494:pharmacology*; D012263:Ribonucleosides / Q000494:pharmacology*; D014372:Tubercidin / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D004791:Enzyme Inhibitors; D011684:Purine Nucleosides; D012263:Ribonucleosides; C018258:3-deazaadenosine; D015762:2-Chloroadenosine; C034583:3-deazaaristeromycin; C005248:nebularine; D006867:Hydrolases; D043383:Adenosylhomocysteinase; D000241:Adenosine; D014372:Tubercidin