1076 CLINICALCHEMISTRY, Vol. 33, No. 6, 1987 second, there was a large paraprotein band at 29 gIL in the beta region, which was determined to be an 1gM-kappa by immunofixation electrophoresis. To determine whether the presence of the paraprotein or an unusual property of this patient’s albumin was responsible for the inability to quantil albumin by bromcresol green binding, I isolated the patie...

We describe an enzymatic method, requiring only 10 mul of serum, for determining CO2 as bicarbonate or dissolved gas. Phosphoenolpyruvate carboxylase catalyzes the reaction of HCO3- with phosphoenolypyruvate to give oxalacetate. The resulting NADH, in the presence of malate dehydrogenase, is oxidized to NAD+, and the decrease in absorbance at 340 nm is directly proportional to the amount of CO2...

An enzymatic method is described for the measurement of vanillyl mandelic acid (VMA). The method utilizes an L-mandelic acid dehydrogenase preparation from Pseudomonas fluorescens A-312 to catalyze the transformation of VMA to vanillin. The method is specific for VMA becauseonly the final product, vanillin, will absorb maximally at 350 m/L. The results compare favorably with the method of Pisan...

We established a simple and rapid enzymatic method for measuring potassium ion in serum by using tryptophanase (EC 4.1.99.1) purified from Escherichia coli K12 strain (E. coli K12 IFO 3301). The presence of pyridoxal 5-phosphate promotes this enzymatic reaction, and potassium and (or) ammonium ions further accelerate it, with ammonium and potassium ions providing equivalent acceleration. We eli...

* Present address, Department of Biochemistry, University of California, Berkeley 4, California. 1 The following abbreviations have been used; THF, tetrahydrofolic acid; lo-formyl-THF, N*o-formyltetrahydrofolic acid; 5,10-methenyl-THF, the cyclic N6-NrOimidazolinium derivative of 5-formyl-THF (anhydroleucovorin or anhydrocitrovorum factor) ; ATP, adenosine triphosphate; ADP, adenosine diphospha...

Background: DBS on filter paper has been shown as a feasible matrix for collection, transport and analysis of biochemical analytes. Creatinine, is used as a marker of renal function and staging chronic kidney disease (CKD), often requiring repeated testing for drug dosing in patients who undergo dialysis or those who have had arenal transplant. Blood collected and dried on filter paper would be...

We describe a highly sensitive and specific method for determining L-carnitine in serum by use of carnitine dehydrogenase (EC 1.1.1.108). The method involves a new enzymatic cycling technique with NADH, thio-NAD+, and carnitine dehydrogenase, and measures the increase of absorbance at 415 nm of thio-NADH produced at 37 degrees C during the reaction: [formula: see text] The calibration curve for...

AIM To study the effect of known interference in the measurement of urea and ammonium concentrations in samples of gastric juice. METHODS The effect of pH and ammonium concentration on the o-pthalaldehyde method, the diacetylmonoxime method, a Berthelot linked method and an enzymatic urease method for the measurement of urea in gastric juice was therefore conducted. An enzymatic method of the...

We describe a manual method, well suited to mechanization, for quantitating serum uric acid at 500 nm. In the assay mixture (0.10 ml of sample and 3.00 ml of reagent) the hydrogen peroxide produced from uric acid by uricase is coupled with p-hydroxybenzoate and 4-aminoantipyrine in the presence of peroxidase to form a colored complex, which is measured. A separate sample blank is obviated by ta...

The techniques of combinatorial chemistry have recently been applied to the discovery of new asymmetric catalysts for a variety of organic transformations.1 These techniques are useful for increasing the efficiency by which chiral ligands for metal catalysts are discovered since the design of these ligands is largely an empirical process, and there are currently no simple rules for reliably pro...