Protease Inhibitor cocktails and specific inhibitors to proteases are important in the protection of proteins from proteolysis in such applications as protein extraction, purification, electrophoresis, storage, assays etc. During isolation and characterization of the proteins, proteases are released following cell or tissue lysis and degrade protein samples, which can reduce the quality of the protein sample for further analysis. In order to prevent degradation of the proteins, protease inhibitor cocktail is added, which help preserve the nature of the protein. G-Biosciences offers a large selection of protease inhibitor cocktails, protease assays and screening systems, phosphatase inhibitor cocktails, as well as specific proteases for use in protein sequencing and mass spectrometry.G-Biosciences offers ProteaseArrest™, which is a broad range of protease inhibitor cocktails with wide species specificity. ProteaseArrest™ cocktails are used for inhibition of protease activity in protein preparations of mammalian, bacteria, plant, yeast and fungal lysates. General protease inhibitors and a large selection of individual protease inhibitors are offered separately or as a protease inhibitor set in addition to the ProteaseArrest™ inhibitor cocktails. For the identification of specific proteases and to screen for the presence of proteases, several protease assays and screening systems are available. For the protection of protein phosphatase groups, PhosphataseArrest™ Phosphatase Inhibitor Cocktails are offered. G-Biosciences offers a selection of specific proteases that are designed for use in peptide fragmentation for mass spectrometry analysis or protein sequencing.