RÉSUMÉ
The effect of addition nucleotides on heparinase production by Flavobacterium heparinum was reseached. The result indicated that addition of nucleotides cause different effects on heparinase production depend on its addi ng mode, single kind of nucleotide would restrain, but multiplex promote. The s trongest promotion happened when the propotion of nucleotides was consistent wit h the nucleic acids of heparinase mRNA. HPLC result confined the entrance of nu cleoides to the bactera cell. And it also suggested the synthesis metabolic of nucleic acids in F.heparinum was imbalance, there always be higher lever of purin nucleoides. L-Asp was added to medium culture to enhance pyridine nucle oides thynesis in order to improve the enzyme production ,which has been affecte d by the imbalance of nucleoides.