Abstract
Ultrasonic resonator technology (URT) was compared with the well established UV–Vis/ninhydrin assay to estimate protease activities in defined buffer systems. Hydrolysis of casein was measured using subtilisin, trypsin, halophilic protease from Haloferax mediterranei and Bacillus lentus alkaline protease. Sensitivity, reproducibility, working range as well as the limit of detection and the limit of quantification were comparable for both methods. Salt concentrations (0.5 M NaCl) interfered with the URT method. The quantification of protease activity by URT was possible when the product concentration measured by the UV–Vis/ninhydrin assay was correlated to the corresponding ultrasonic velocity signals.
Similar content being viewed by others
References
Freyer EB (1931) Sonic studies of the physical properties of liquids. II. The velocity of sound in solutions of certain alkali halides and their compressibilities. J Am Chem Soc 53:1313–1320
Kamekura M, Seno Y (1993) Partial sequence of the gene for a serine protease from halophilic archaeum Haloferax mediterranei R4, and nucleotide sequences of 16S rRNA encoding genes from several halophilic archaea. Experientia 49:503–513
McClements DJ (1991) Ultrasonic characterization of emulsions and dispersions. Adv Colloid Interface Sci 37:33–72
Moore S, Stein W (1954) A modified ninhydrin reagent for the photometric determination of amino acids and related compounds. J Biol Chem 211:907–913
Povey MJW (1997) Ultrasonic techniques of fluids characterization. Academic Press, San Diego
Richardson PL (2002) The determination and use of optimized protease substrates in drug discovery and development. Curr Pharm Des 8:2550–2581
Sarvazyan AP (1991) Ultrasonic velocimetry of biological compounds. Annu Rev Biophys Chem 20:321–342
Ulrick RJ (1947) A sound velocity method for determining the compressibility of finely divided substances. J Appl Phys 18:983–987
Author information
Authors and Affiliations
Corresponding author
Additional information
Karin Born and Anja Manns have contributed equally to this work.
Rights and permissions
About this article
Cite this article
Born, K., Manns, A., Dzeyk, K. et al. Evaluation of ultrasound velocity measurements for estimating protease activities using casein as substrate. Biotechnol Lett 32, 249–253 (2010). https://doi.org/10.1007/s10529-009-0135-x
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10529-009-0135-x