1987 年 45 巻 4 号 p. 385-392
This article reviews recent developments in use of microbial enzymes for clinical analysis and new trends in production of the enzymes by use of genetic engineering techniques. The increased availability of microbial enzymes has led to many analytical applications in the areas of clinical chemistry. Especially during the last decade enzymatic assays have rapidly spred in clinical laboratories through efforts of the search of useful enzymes. The applications of cholesterol oxidase to the determination of serum cholesterol showed that the enzymatic method was more specific, precise and sensitive than the chemical method. This success stimulated developments and adoptions of other enzymatic assays for triglycerides, phospholipids and free fatty acids. The principle of enzymatic methods are mainly based on either the colorimetric assay of hydrogen peroxide formed during the reaction by oxidase or the spectrophotometric determination of the change of NAD (P) linked with dehydrogenase. Whether the enzymatic method can prove its worth or not depends on properties of microbial enzymes used in the assay. The enzymes have to be equipped with enough qualifications in specificity, affinity, optimum pH and stability. The advance in gene-splicing technology made it possible to produce microbial enzymes at high levels and the cloned N-acetylneuraminate lyase has become the first enzyme to be used in clinical laboratories. Protein engineering also gives us possibilities that properties of the enzymes are improved to be more suitable for clinical analysis.