Cutinase belongs to the family of serine hydrolases which are capable of hydrolysis of esters and small polyester such as cutin. The cutin of plants is composed of hydroxy and epoxy fatty acids and is substantially imperm-eable to water and only the plant pathogenic bacteria are capable of degrading it. Initially, in order to identify the extent of cutin in cucumber (Cucumis sativus' C. sativus'), golden apples (Golden Delicious apple 'Malus domestica'), red ap-ples (Red Delicious apple 'Malus domestica'') and tomatoes (Solanum lycopersicum Mill. Commun ' S. lycopersicum'), their fruits were obtained. Cutin was extracted from the fruit skin of each studied specimen and compared by chloro-form-methanol method. Then, isolation of enzyme-producing strains was performed by the use of the specific medium containing cutin and enzyme activity assay. DNA of the specimens was extracted, and PCR were performed with univ-ersal primers for 16s DNA. The remainder was devoted to bioinformatic analysis, identification and registration of samples in the gene bank. The results showed that the percentage of extracted cutin in red apple was more than other samples and as a result, red apple are expected to be more resistant against diseases and pests. Also, six cutinase-prod-ucer strains of Klebsiella and Enterobacter were isolated with the help of enzyme activity and special culture medium containing cutin, and their 16s DNA region coding sequences were recorded in the GenBank.

Cutin is a polymer that is constructed in plants by the condensation and oxidation of fatty acids and plays a key role in the protection of plants against pathogens. Cutinase is a hydrolase enzyme that breaks down the cutin. The purpose of this study was to extract cutin from red apples with oxalate buffer, cutinase enzyme activity assay in LB culture, and bioinformatic analysis. To attain these purposes the cutinase-producing strains that had previously been isolated were inoculated in culture medium containing cutin. After initial culture, the bacteria were cultured in LB medium and cutinase activity was measured using the p-Nitrophenyl butyrate. In order to execute bioinformatic analysis, the isolated sequences of six cutinase-producing bacteria were analyzed based on computational data bases and their phylogenetic trees were prepared. Then, the similarities in the sequences of a large number of cutinase-producing samples were analyzed by drawing the phylogenetic tree. The results showed the separation of cutinase-producing prokaryotes from cutinase-producing eukaryotes. Then, the sequence of 16S rDNA of these cutinase-producing samples as well as the samples we had prepared were evaluated and their phylogenetic relationships were determined. This analysis showed that the new sequence stood alongside the bacterial samples. Thus, our cutinases may be similar with these bacterial cutinases in structure and function.