Biochemical Properties and Antibacterial Activity of Lactoferrin from Korean Native Cow

한우 Lactoferrin의 생화학적 특성 및 항균 활성

The purpose of this study was to demonstrate biochemical properties and antibacterial activity of lactoferrin(Lf) obtained from the colostrum of Korean native cow. Lactoferrin was isolated from the colostrum of Korean native cow by purification steps using batch extraction, ion exchange chromatography, gel filtration chromatography, affinity chromatography. Other whey protein components that is similar molecular weight and affinity to lactoferrin were gradually removed from crude Korean Native cow's lactoferrin during the purification steps. The molecular weight of the purified Korean native cow's Lf(K-Lf) was 81 kDa, the isoelectric point was 9, and the content of iron was 0.56mg/g, which is indicated that iron saturation of the K-Lf was 40.6%. Amino acid composition and a-helix content were different K-Lf from bovine Lf(B-Lf). Antibacterial activity of E. coli O111 by K-Lf was lower than that of B-Lf. A minimal inhibitory concentration(MIC) of K-Lf and B-Lf was 2.75mg/ml and 1.5mg/ml respectively.

우리나라 재래종인 한우의 초유로부터 lactoferrin(Lf)을 분리하기 위해서 batch extraction, ion exchange chromatography, gel filtration chromatography, affinity chromatography 등의 정제과정을 실시하였다. 각 정제 단계에 의해 한우 Lf과 결합되어 있던 여러 물질들이 제거되었으며 한우 초유 1 liter에서 정제과정을 통하여 회수한 Lf의 양은 65mg로 회수율이 29.4%였다. SDS-PAGE와 HPLC를 이용해 확인한 결과, 정제 단계를 거침에 따라 순도가 높아지는 것 알 수 있었다. 정제된 한우 Lf은 분자량이 81 kDa 이고 등전점은 pI 9였으며, 철 함량이 0.56mg/g으로 철 포화도는 약 40.6%로 측정되었다. 한우 Lf과 젖소 Lf은 아미노산 조성과 ${\alpha}$-helix 함량에서 서로 다르게 나타났다. E. coli O111에 대한 항균성은 젖소 Lf이 한우 Lf 보다 높았으며, 최소저해농도(MIC)는 젖소 Lf이 1.5mg/ml, 한우 Lf은 2.75mg/ml로 젖소 Lf의 항균 활성이 더 높은 것으로 나타났다.