Abstract: A two reagent-type kit for assaying GPT by acting GPT on L-alanine and &agr;-ketoglutarate in the presence of pyridoxal phosphate, converting the resulting pyruvate into lactate with L-lactate dehydrogenase (LDH) in the presence of reduced nicotinamide adenine dinucleotide (NADH) and measuring GPT based on a decrement of NADH, the GPT assay kit comprising a first reagent and a second reagent, one of which contains pyridoxal phosphate, L-alanine, &agr;-ketoglutarate, LDH and NADH and the other reagent contains no pyridoxal phosphate but contains L-alanine. The GPT assay kit is stable over a long period of time.

Abstract: By making a bilirubin oxidase derived from the genus Pleurotus to act on a living body fluid sample in the presence of at least one of a cationic surfactant such as alkyltrimethylammonium salt, etc. and a nonionic surfactant such as polyoxyethylenealkyl ether, etc., only bilirubin non-.delta. fractions of the living body fluid sample can be oxidized, while keeping a bilirubin .delta. fraction remaining as unreacted. Thus, the bilirubin non-.delta. fractions and .delta. fraction of the living body fluid sample can be exactly quantitatively determined by action of the bilirubin oxidase on the sample.

Abstract: A method of measuring urea nitrogen on the basis of the ultraviolet absorption of urease-GLDH by a reaction rate method, which method not only permits accurate measurement of a sample containing a high concentration of urea nitrogen but also permits accurate measurement of a sample containing polyols such as mannitol without suffering the influence of the polyols, the method comprising hydrolyzing urea in a sample with urease, reacting glutamate dehydrogenase (GLDH) with ammonia formed by the hydrolysis, in the presence of .alpha.-ketoglutaric acid (.alpha.-KG) and reduced-type nicotineamide adenine dinucleotide (NADH) or reduced-type nicotineamide adenine dinucleotide phosphate (NADPH), and measuring the reduced-type nicotineamide adenine dinucleotide (NADH) or reduced-type nicotineamide adenine dinucleotide phosphate (NADPH) for a decrease rate to measure urea nitrogen derived from the urea, and characterized in that a sulfhydryl compound is co-present with the urease.

Abstract: Total bilirubin or direct bilirubin is measured by allowing nitrous acid as an oxidizing agent to act on a sample of living body fluid, and measuring optical changes of the sample. For measuring the direct bilirubin, nitrous acid is allowed to act on the sample in the presence of thiourea as a reaction inhibitor for indirect bilirubin. For measuring the total bilirubin, nitrous acid is allowed to act on the sample in the presence of cetyltrimethylammonium bromide as a reaction accelerator. Or, direct bilirubin is measured by allowing an oxidizing agent to act on a sample of living body fluid in the presence of a specific non-ionic surfactant. These methods have a good correlation to the conventional enzymatic method and a good reagent stability and provide safe methods for measuring bilirubin with less danger to environmental pollution.

Abstract: According to the present invention, there are provided a monoclonal antibody to prostate-derived acid phosphatase and a method for determination of prostate-derived acid phosphatase using the monoclonal antibody. Prostate-derived acid phosphatase is boostered in animal and spleen cells isolated from the animal are fused with myeloma cells. The hybridoma capable of producing a monoclonal antibody having extremely high specificity to prostate-derived acid phosphatase is subjected to cloning. Using the monoclonal antibody produced by the hybridoma, prostate-derived acid phosphatase in a sample can be detected with extremely high sensitivity.

Abstract: A method of measuring the total ketone body in a sample comprising converting acetoacetic acid in the sample to 3-hydroxybutyric acid in advance and subsequently converting the whole 3-hydroxybutyric acid including 3-hydroxybutyric acid existing in the sample originally to acetoacetic acid to lead the reduction of nicotinamide adenine dinucleotide according to the action of 3-hydroxybutyrate dehydrogenase and a sample reagent thereof is disclosed. According to this invention an assay of the total ketone body in samples can be carried out conveniently, highly precisely and quickly.

Abstract: Novel N-acetyl-.beta.-D-glucosamine derivatives and a method for assaying N-acetyl-.beta.-D-glucosaminidase activity using the same as substrate are provided.N-Acetyl-.beta.-D-glucosamine derivatives represented by general formula (I): ##STR1## wherein each of R.sub.1 and R.sub.2 independently represents hydrogen atom or methyl or ethyl group, are mixed with a sample containing N-acetyl-.beta.-D-glucosaminidase (NAG) and then absorbance of the reaction solution is determined to assay NAG activity extremely accurately.

Abstract: Phosphoric acid derivatives represented by formula (I): ##STR1## wherein X is a halogen and R is --(CH.sub.2).sub.n CH.sub.3 (n=0 to 3), or salts thereof are stable to non-enzymatic hydrolysis and are capable of specifically reacting with acid phosphatase. Therefore, the activity of acid phosphatase in the sample can be determined extremely accurately by reacting said compound with a sample containing acid phosphatase and quantitatively determining the reaction product by colorimetry.

Abstract: There is provided a method for determination of hydroxyacetophenone derivatives such as 3,5-dichloro-4-hydroxyacetophenone in the presence of protein such as albumins or globulins with high sensitivity. The hydroxyacetophenone derivative can be measured in the neutral to acidic region, whereby the method is not affected by interferrants such as bilirubin or hemoglobin. The hydroxyacetophenone derivatives are useful as the chromogen of synthetic substrates for determining acid phosphatase activity.

Abstract: Novel compounds represented by the following formula: ##STR1## wherein A represents a specific amino acid residue are excellent as substrates for determination of enzyme activity such as trypsin, etc. The compounds can be synthesized from novel arginyl-3-tert-alkyloxycarbonyl-4-nitroanilides by a novel process comprising a selective deprotection step whereby the protecting group on the .alpha.-amine group of arginine is removed in the presence of a hydrochloric acid, acetic acid and dimethylformamide mixture, but a tert-alkyl protecting group on the --COOH group of the nitroanilide ring is not removed by this step.

Abstract: Phosporic acid derivatives represented by formula (I): ##STR1## wherein X is a halogen and R is --(CH.sub.2).sub.n CH.sub.3 (n=0 to 3), or salts thereof are stable to non-enzymatic hydrolysis and are capable of specifically reacting with acid phosphatase. Therefore, the activity of acid phosphatase in the sample can be determined extremely accurately by reacting said compound with a sample containing acid phosphatase and quantitatively determining the reaction product by colorimetry.

Abstract: A novel compound, 6-acetoxymethyl-2-naphthoylcholine halide, is very stable to nonenzymatic hydrolysis and react specifically with cholinesterase in serum. A UV method for determining cholinesterase activity in serum which uses the novel compound as a substrate permits very accurate and highly reproducible determination of cholinesterase activity in serum, and therefor is very useful for clinical examination.

Abstract: This invention relates to a method for determination of cholinesterase activity, characterized by using, as a substrate, a choline derivative represented by the general formula (I): ##STR1## wherein X is a halogen atom; Y.sub.1 is a hydroxyl group as a substituent in the 2- or 5-position; and Y.sub.2 is a hydroxyl group as a substituent in the 3-position.The determination method of this invention permits easy and simple determination of cholinesterase activity, and is very useful as a determination method for clinical examinations for the purpose of determining cholinesterase in serum.

Abstract: In a method for determining cholinesterase (hereinafter referred to as ChE) activity, the improvement comprising by using, as a substrate, a protocatechuoylcholine derivative represented by the general formula (I), ##STR1## (wherein X is a halogen atom). The method for determining ChE activity according to the present invention is free from defects of the conventional methods, has many advantages and characteristics, permits accurate and simple determination of ChE activity, and can sufficiently contribute to determination of ChE activity in daily clinical examinations.