Abstract

To investigate the lowering effects of in vitro enzymatic hydrolysis by the treatment of chymotrypsin, trypsin, pancreatin, or protease from Aspergillus oryzae on the antigenicity of whey protein isolate (WPI) against rabbit anti ${\alpha}-LA$ antiserum, competitive inhibition ELISA (cELISA) and passive cutaneous anaphylaxis (PCA) test using guinea pig were performed. The results of cELISA showed that the monovalent antigenicity of the whey protein hydrolysates (WPH) to the antiserum was decreased to $10^{-2.5}-10^{-5.5}$ and less by the hydrolysis. The monovalent antigenicity of the WPH hydrolyzed by trypsin, or protease from Asp. nryzae was much lowered by the pretreatment of heat denaturation. The antigenicity of the WPH hydrolyzed by chymotrypsin, trypsin, or pancreatin was much lowered by the pretreatment of pepsin. Especially, the antigenicity of TDP (trypic hydrolysate with pretreatment of heat and pepsin) was found almost to be removed. However, there was not consistency between degree of hydrolysis(DH) and the monovalent antigenicity of the WPH. By the heterologous PCA it was found that all of the PGPH lost the polyvalent antigenicity regardless of the pretreatments although WPI and ${\alpha}-LA$ had the positive high antigenicity. The results suggested that the peptides derived from ${\alpha}-LA$ in WPH could bind specific antibodies but they could not induce allergy. Therefore, it was elucidated that the allergenicity of ${\alpha}-LA$ in whey protein could be destroyed easily by the enzymatic hydrolysis.

Chymotrypsin, trypsin, pancreatin, 그리고 Aspergillus oryzae 유래 단백질분해효소의 in vitro처리에 의하여 유청단백질(WPI)의 가수분해물(WPH)중 ${\alpha}-LA$ 유래의 항원성변화를 조사하기 위하여 토끼 항 ${\alpha}-LA$ 항혈청을 이용한 competitive inhibition ELISA(cELISA)와 heterologous PCA를 실시하였다. cELISA에 의하여 WPH의 monovalent항원성을 분석한 결과, pepsin전처리는 chymotrypsin, trypsin 그러고 pancreatin 가수분해물의 항원성을 더욱 감소시키는 효과가 있었으며, 열 전처리는 Asp. oryzae 유래효소 및 trypsin 가수분해물의 항원성을 더욱 감소시켰다 전체적으로 ${\alpha}-LA$유래의 monovalent 항원성은 효소처리에 의하여 $10^{-2.5}-10^{-5.5}$배 또는 그 이하로 저하되었으며, 특히 열 및 pepsin 전처리후 trypsin으로 가수분해한 경우(TDP)의 항원성은 거의 상실되었다. WPH의 가수분해도와 ${\alpha}-LA$유래의 monovalent 항원성 감소는 그다지 일치하지 않았다. Guinea pig를 이용한 PCA test에 의하여 ${\alpha}-LA$유래의 polyvalent 항원성을 분석한 결과 WPI 및 ${\alpha}-LA$는 양성으로 높게 나타났으나, WPH는 전처리유무에 관계없이 모두 음성으로 나타났다. 이는 WPI의 가수분해로 생성된 ${\alpha}-LA$유래의 peptide가 특이항체와 결합은 가능하나 생체내에서 알레르기를 유발하지 않음을 뜻하였다. 따라서, 유청단백질을 효소로 가수분해하면 유청단백질중 ${\alpha}-LA$의 allergenicity는 쉬 파괴됨을 알 수 있었다.

Keywords

• whey protein hycrolysate;
• antigenicity;
• rabbit anti ${\alpha}-Lactalbumin$ antiserum;
• competitive inhibition ELISA;
• heterologous PCA