Kumar A Kiran, Goswami Pranab
Department of Biotechnology, Indian Institute of Technology Guwahati, North Guwahati, Assam 781039, India.
Appl Microbiol Biotechnol. 2006 Oct;72(5):906-11. doi: 10.1007/s00253-006-0381-y. Epub 2006 Mar 18.
Short chain alcohol oxidase (SCAO), long chain alcohol oxidase (LCAO), secondary alcohol oxidase (SAO), and aryl alcohol oxidase (AAO) activities were localized in the microsome of Aspergillus terreus during growth of the fungi on n-hexadecane. Zymogram analysis of the microsomes of n-hexadecane-grown cells in polyacrylamide gel electrophoresis showed distinct bands, H4, H3, H2, and H1, in a sequence of their molecular weight (Mr) from high to low. The Mr of the isozymes corresponding to the bands H4, H3, and H2 were close to each other and were higher than 272 kDa. While, the Mr of the isozyme H1 was found to be approximately 48 kDa. H1 gave activity only as SCAO. Although the substrates for other bands were varied, strong (S), medium (M), and weak (W) activity for the bands were as follows: H2: SAO (S), AAO (S), LCAO (M), SCAO (S); H3: LCAO (S), SCAO (S); H4: SCAO (S), LCAO (W), SAO (W). The pH and temperature optima of these isozymes were found to be 8.5+/-0.5 and 30+/-1 degrees C, respectively. The stability of the isozymes was drastically decreased beyond 30 degrees C. The SAO showed 33% enantiomeric excess for the R(-)2-octanol over S(+)2-octanol, which may be correlated with the lower Michaelis-Menten constant (K (M)) values of the enzyme for the R(-)2-octanol than the S(+)2-octanol. The fluorescence emission spectra of the chromatographically purified SCAO at 443 nm excitation were similar to that obtained with authentic flavin adenine dinucleotide.
在土曲霉在正十六烷上生长期间，短链醇氧化酶（SCAO）、长链醇氧化酶（LCAO）、仲醇氧化酶（SAO）和芳基醇氧化酶（AAO）活性定位于其微粒体中。在聚丙烯酰胺凝胶电泳中对在正十六烷上生长的细胞的微粒体进行酶谱分析，显示出不同的条带，H4、H3、H2和H1，按照分子量（Mr）从高到低的顺序排列。与条带H4、H3和H2相对应的同工酶的Mr彼此接近且高于272 kDa。而条带H1的同工酶的Mr约为48 kDa。H1仅作为SCAO具有活性。尽管其他条带的底物各不相同，但这些条带的强（S）、中（M）和弱（W）活性如下：H2：SAO（S）、AAO（S）、LCAO（M）、SCAO（S）；H3：LCAO（S）、SCAO（S）；H4：SCAO（S）、LCAO（W）、SAO（W）。发现这些同工酶的最适pH和温度分别为8.5±0.5和30±1℃。超过30℃时，同工酶的稳定性急剧下降。SAO对R(-)2-辛醇比对S(+)2-辛醇表现出33%的对映体过量，这可能与该酶对R(-)2-辛醇的米氏常数（K (M)）值低于S(+)2-辛醇有关。经色谱纯化的SCAO在443 nm激发下的荧光发射光谱与用 authentic黄素腺嘌呤二核苷酸获得的光谱相似。
