Study of different hormone-sensitive lipase concentrations using a surface plasmon resonance sensor

This paper presents a series of experimental results including those based on the surface plasmon resonance (SPR) to investigate the parameters for determining the concentration and form of various hormone sensitive lipase (HSL) solutions. HSL is a rate-limiting enzyme for the metabolism of stored fat. This small protein was not previously known to possess optical properties permitting studies by attenuated total internal reflection (ATR) spectroscopy or by the SPR method. Therefore, basic physical measurements were needed. The HSL solutions are typically contained in different buffers that chemically affect the metal layers in the SPR experiments and cause problems with film integrity. Different experiments employing different metal layers were conducted. The results were compared with those of the ATR method, showing the expected greater sensitivity of the surface plasmon resonance method. It was determined that the protein solutions may be usefully examined by both methods ultimately permitting measurement of oligomer formation as a function of concentration in future work.