Purification and characterization of deoxyribonuclease from small intestine of camel Camelus dromedarius

Somia S Abdel-Gany; Mohamed O El-Badry; Afaf S Fahmy; Saleh A Mohamed

doi:10.1016/j.jgeb.2017.06.008

Purification and characterization of deoxyribonuclease from small intestine of camel Camelus dromedarius

J Genet Eng Biotechnol. 2017 Dec;15(2):463-467. doi: 10.1016/j.jgeb.2017.06.008. Epub 2017 Jun 28.

Authors

Somia S Abdel-Gany¹, Mohamed O El-Badry¹, Afaf S Fahmy¹, Saleh A Mohamed^{1

2}

Affiliations

¹ Molecular Biology Department, National Research Centre, Cairo, Egypt.
² King Abdulaziz University, Department of Biochemistry, Jeddah, Saudi Arabia.

Abstract

The chromatography of deoxyribonuclease (DNase) from small intestine of camel Camelus dromedarius by DEAE-Sepharose separated three isoforms DNase 1, DNase 2 and DNase 3. The DNase 3 was purified to homogeneity by chromatography on Sephacryl S-200. The molecular weight of DNase 3 was 30 kDa using gel filtration and SDS-PAGE. The pH optimum of DNase 3 was reported at 7.0 using Tris-HCl buffer. The temperature optimum of DNase 3 was found to be 50 °C. The enzyme was stable up to 50 °C for one h incubation. The Km value was 28.5 µg DNA, where this low value indicated the high affinity of enzyme toward DNA as substrate. No activity of DNase 3 was determined in the absence of metal cations. Mg²⁺ and Ca²⁺ caused significant enhancement in the enzyme activity by 90 and 75%, respectively. The mixture of Mg²⁺ and Ca²⁺ caused 100% of enzyme activity. Ni²⁺, Co²⁺, Ba²⁺, Zn²⁺ and Cd²⁺ showed very strong inhibitory effect on enzyme activity. In conclusion, the characterization of DNase 3 indicated that the enzyme is considered as a member of DNase I family. The low Km value of the DNA suggested that the high digestion of DNA of camel forage by small intestine DNase 3.

Keywords: Camel; Deoxyribonuclease; Small intestine.