An Effective Method of Isolating Immunoglobulins from Bovine Plasma Proteins

도축혈액으로부터 면역단백질의 효과적인 분리법

Imunoglobulins from bovine plasma proteins were isolated by IMAC which $Cu^{2+}$ was chelated on a chelating sepharose fast flow gel. Most plasma proteins were eluted by 1st (0.01 M $Na_2HPO_4$, 0.5 M NaCl, pH 4.0) and 2nd elution buffers (0.01 M imidazol). According to the reverse phase HPLC analysis, it was found that proteins which were eluted by 1st elution buffer were mainly composed of serum albumin, while most IgG and transferrin were eluted by 2nd elution buffer. When protein fractions obtained by 2nd elution buffer was applied to ultra filtration system (molecular weight cut off: 100 kD), IgG was further purified. These results indicate that IMAC is an excellent tool for isolating imunoglobulins from plasma proteins.

Chelating sepharose fast flow gel에 $Cu^{2+}$을 고정화시키고 이들과 단백질과의 친화력 정도에 의해서 용출용매를 통해 단백질을 분획하는 방식의 IMAC법을 이용하여 소의 혈장단백질로부터 IgG의 분리를 시도하였다. 대부분의 혈장단백질은 1차(0.01 M $Na_2HPO_4$, 0.5 M NaCl, pH 4.0)와 2차 용출용매(0.01 M imidazol)에 의하여 용출되었으며 역상 chromatography를 이용하여 각 분획의 단백질조성을 조사한 결과, 1차 용출용매에 의해서는 주로 albumin이, 그리고 2차 용출용매에 의해서는 IgG와 transferrin 등이 IMAC column으로부터 용출되었다. 2차 용출용매에 의해 얻어진 분획으로부터 분자량 100 kD이상의 단백질을 한외여과장치를 이용하여 농축하였을 때, IgG가 효과적으로 분리 정제 되었다.