사람의 미토콘드리아에 있는 aldehyde dehydrogenase(ALDH2)는 체내에서 알코올 대사 과정 중에 생성되는 아세트알데히드를 산화시키는 주된 역할을 담당하고 있다. 이 ALDH2가 알코올 대사에 미치는 영향을 연구하기 위하여 가용화된 효소가 팔요하다. 알려져 있는 유전자의 염기서열 데이터를 바탕으로 ALDH2의 cDNA는 cDNA 라이브러리에서 선별하였으며, 이를 여러 가지 대장균 발현벡터에 연결하였다. 제조한 발현벡터를 형질전화시킨 대장균을 사용하여 단백질의 발현을 확인한 결과 대부분의 계에서 ALDH가 과발현되고 있었다. 그러나 발현된 단백질의 대부분은 inclusion body로 형성되어, 실제로 가용화된 효소의 양은 전체 발현된 양의 5% 이하였고 이들 몇 가지 발현 system으로 재조합 ALDH2의 발현을 확인하였다.
In order to obtain the fundamental informations on cellulase of Trichoderma viride QM 9414 for its production and utilization, some physico-chemical properties of the enzyme were reviewed. When T. viride QM 9414 was cultured on wheat bran medium, filter paper-disintegrating and carboxymethyl cellulose(CMC)-saccharifying activity were incresed with the cell growth, and thereafter CMC-saccharifying activity was kept on almost the same leved while filter-paper disintegrating activity was decreased sharply. And β-glucosidase was formed maximally on the late stationary phase of growth. The crude cellulase of cell-free extracts was purified by (NH_4)_2SO, fractionation, Sephadex-G 200 column chromatography and DEAE Sephadex A-50 column chromatography. Filter paper-disintegrating, CMC-saccharifying and β-glucosidase activity were purified 10-fold, 47-fold and 38-fold, respectively. The crude enzyme was proved to be a complex of three different enzyme proteins which were showing filter paper-disintegrating, CMC-saccharifying and β-glucosidase activity. The optimal pH of the three enzyme components was alike pH 4.0, and the optimal temperature for CMC-saccharifying, filter paper-disintegrating and β-glucosidase activity were 40℃, 45℃ and 50℃ respectively. The Km and Vmax values of CMC saccharifying activity for CMC were 0.485% and 3.10(μmole/min·㎖), and the Km and Vmax values of β-glucosidase for ONPG(o-nitrophenol glucopyranoside) were 0.944×10 exp (-3)M and 0.097(μmole/min·㎖), respectively. The Km and Vmax values of filter paper-disintegrating activity for Avicel were determined to be 0.09% and 0.178(μmole/min·㎖), respectively. β-Glucosidase activity was competitively inhibited by glucose, and the Ki value for this enzyme was 3.54×10 exp (-3)M, CMC saccharifying activity was found to be greatly inhibited by cellobiose.