Two genes, orf6 and orf9 located in the L-oleandrose sugar biosynthetic gene cluster of Streptomyces antibioticus $T{ddot{u}}99$. NovU has been characterized as C-5 methyltmaferase involved in noviose biosynthetic pathway. We have cloned and heterologously expressed the orf6, orf9, and novU genes in S. venezuelae YJ003-OTBP1. This established the function of orf6 and orf9 as 4-ketoreductase and 3-epimerase, respectively. All of analytical data of the noviosylated 10-deoxymethynolide also is in support of proving their functions. Furthermore biosynthetic pathway 5,5-gem-dimethyl-6-deoxyglucose (TDP-L-noviose) has been proposed.