title: Deoxyribosyl transfer catalysis with trans-N-deoxyribosylase. Kinetic study of purine(pyrimidine) to pyrimidine(purine) trans-N-deoxyribosylase.
abstract: Kinetic studies were carried out in order to investigate the enzymic mechanism of a 215-fold-purified purine(pyrimidine) nucleoside: purine(pyrimidine) deoxyribosyl transferase fraction from Lactobacillus helveticus. A variety of natural deoxyribonucleosides and bases were used as substrates. Initial velocity, product inhibition and isotopic exchange studies are consistent with a ping-pong bi-bi mechanism. The kinetic parameters are used to show that this fraction is free from any contamination by a specific purine nucleoside: purine deoxyribosyl transferase also found in the same strain of L. helveticus.
mesh_terms: D000225:Adenine / Q000494:pharmacology; D003839:Deoxyadenosines / Q000494:pharmacology; D003841:Deoxycytidine / Q000494:pharmacology; D003853:Deoxyribonucleosides / Q000378:metabolism*; D007778:Lactobacillus / Q000201:enzymology; D008433:Mathematics; D010430:Pentosyltransferases / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D003839:Deoxyadenosines; D003853:Deoxyribonucleosides; D003841:Deoxycytidine; D010430:Pentosyltransferases; D000225:Adenine