โ Scribed by R.L. Zimmerman Jr.; G.G. Guilbault
No coin nor oath required. For personal study only.
and Zimmerman' have reported the first successful solid-surface method for monitoring the rate of an enzyme reaction; the enzyme cholinesterase was determined.
In the present paper a method for another clinically important enzyme. lactic dehydrogcnasc (LDH) is presented. Before any strum samples were analyzed. the method was optimized for commercially available rabbit muscle LDH. The results of those experiments and the optimal conditions arc reported. Many authors have reported fluorimctric methods for the determination of both lactic acid2. and LDH"sJ by means of the enzyme-catalyzed reaction Li lactate + NAD G==== NADH + pyruvic acid (1) or some variation of this reaction". Bcrgmeycr et ~1.~ have also described a method for the determination of serum LDH based on this equation ; this method involves monitoring the disappearance of NADH at 340 nm. This standard assay procedure is compared to the method reported herein. A technique described by Cabaud and Wroblcwski' was used by the hospital from which the sera were obtained. The LDH values from this method were used as the "true" LDH content. Vaughan and Guilbault* have developed a new and better cell design than that originally used by Guilbault and Zimmerman '. They also altered the pad design in order to enhance the reproducibility and accuracy of the semi-solid surface method. A third innovation they employed was the turning of the fluorimeter onto its side so that the pad, and drop of enzyme solution, would sit in a horizontal position in the fluorimeter. No adverse effects on the instrument were noted. Normal ranges of the LDH content of healthy human blood serum have been reported by many authors to vary between 150 and 680 units per ml of serum9-il. Therefore, special attention was paid to samples possessing LDH values in this range. Sample values of LDH concentration were taken outside the above range in both directions for the commercial LDH, but the source of serum samples could not provide sera any lower than 160 units ml -1 at the time the analyses were performed. Sera with LDH values above 820 did not fit the linear calibration plot. Sera with LDH values between 620 and 820 were also not available.
๐ SIMILAR VOLUMES
Interfacial solid/liquid interactions play a crucial role in wetting, spreading, and adhesion processes. In the case of a flat solid surface, contact angle measurements are commonly utilized for the determination of the solid surface free energy and its components. However, if such a surface cannot