Richard P, Londesborough J, Putkonen M, Kalkkinen N, Penttilä M
VTT Biotechnology, P.O. Box 1500, Espoo, FIN-02044 VTT, Finland.
J Biol Chem. 2001 Nov 2;276(44):40631-7. doi: 10.1074/jbc.M104022200. Epub 2001 Aug 20.
L-Arabinitol 4-dehydrogenase (EC ) was purified from the filamentous fungus Trichoderma reesei (Hypocrea jecorina). It is an enzyme in the L-arabinose catabolic pathway of fungi catalyzing the reaction from L-arabinitol to L-xylulose. The amino acid sequence of peptide fragments was determined and used to identify the corresponding gene. We named the gene lad1. It is not constitutively expressed. In a Northern analysis we found it only after growth on L-arabinose. The gene was cloned and overexpressed in Saccharomyces cerevisiae, and the enzyme activity was confirmed in a cell extract. The enzyme consists of 377 amino acids and has a calculated molecular mass of 39,822 Da. It belongs to the family of zinc-binding dehydrogenases and has some amino acid sequence similarity to sorbitol dehydrogenases. It shows activity toward L-arabinitol, adonitol (ribitol), and xylitol with K(m) values of about 40 mM toward L-arabinitol and adonitol and about 180 mM toward xylitol. No activity was observed with D-sorbitol, D-arabinitol, and D-mannitol. NAD is the required cofactor with a K(m) of 180 microM. No activity was observed with NADP.
L-阿拉伯糖醇4-脱氢酶（EC ）是从丝状真菌里氏木霉（枝状曲霉）中纯化得到的。它是真菌L-阿拉伯糖分解代谢途径中的一种酶，催化从L-阿拉伯糖醇到L-木酮糖的反应。测定了肽片段的氨基酸序列，并用于鉴定相应的基因。我们将该基因命名为lad1。它不是组成型表达的。在Northern分析中，我们仅在L-阿拉伯糖上生长后才发现它。该基因被克隆并在酿酒酵母中过表达，并且在细胞提取物中证实了酶活性。该酶由377个氨基酸组成，计算分子量为39,822 Da。它属于锌结合脱氢酶家族，与山梨醇脱氢酶有一些氨基酸序列相似性。它对L-阿拉伯糖醇、阿东糖醇（核糖醇）和木糖醇有活性，对L-阿拉伯糖醇和阿东糖醇的K(m)值约为40 mM，对木糖醇的K(m)值约为180 mM。对D-山梨醇、D-阿拉伯糖醇和D-甘露醇未观察到活性。NAD是所需的辅因子，K(m)为180 microM。对NADP未观察到活性。
