More human islet isolations have been performed using purified collagenase and thermolysin than any other purified enzyme mixture (1). Several reports have shown the adverse effects when using thermolysin for human islet isolation (2, 3). This blog post reviews the truth and fiction when using thermolysin for human islet isolation. It will also briefly discussRead more about Thermolysin & human islet isolation: Truth vs. Fiction[…]

The introduction of Liberase™ HI Purified Enzyme Blend in 1994 to improve the consistency of enzymes used to recover human pancreatic islets for subsequent transplantation contributed to the growth of clinical islet transplantation.(1)  Liberase™ HI set a benchmark for comparing the performance of all subsequent products used for this application.(2, 3) A series of reportsRead more about New insights for using purified enzymes in human islet isolation[…]

The transition of enzyme suppliers in 2007 from Liberase™ HI to Nordmark/Serva’s NB-1 collagenase & NB protease for isolation of human islets used in Collaborative Islet Transplantation consortium clinical trial was problematic for some expert islet labs but not for others. During this period, the number of allo-islet transplantations performed in North America was atRead more about Variability in islet yields may be due to the molecular form of class 1 collagenase[…]

Current lot qualification process Lot selection of traditional Clostridium histolyticum collagenase (i.e., crude or enriched) products is a time consuming process. Typically, you request small samples from one or more new lots of the collagenase product you currently use.  You evaluate their ability to recover sufficient numbers of functional cells, as compared to your currentRead more about Learning from lot qualification[…]

Simple approach to optimize collagenase enzyme mixtures to improve cell recovery Current state of the art No simple method exists for defining optimal collagenase enzyme formulations for the recovery of primary cells from tissue. The unknown biochemical composition of traditional crude or enriched collagenase products, combined with variability in enzyme activities between each lot ofRead more about Simple approach to optimize collagenase enzyme mixtures to improve cell recovery[…]

Setting a new paradigm for low cost collagenase The current paradigm for collagenase: Crude collagenase is impure, as reflected by the brown to black color of the product. Biochemical heterogeneity between different lots of crude collagenase is due to impurities and is reflected by inconsistent results after use in cell isolation procedures. Collagenase products areRead more about Setting a new paradigm for low cost collagenase[…]

Does collagenase truly deserve top billing as the key enzyme for isolating primary cells? Collagenase quality For many years, experts in cell isolation have stated the importance of collagenase quality for successful cell isolation.1,2 What does collagenase quality mean? Many investigators have found it difficult to correlate the enzymatic analysis data summarized on a CertificateRead more about Does collagenase truly deserve top billing as the key enzyme for isolating primary cells?[…]

Over the past several years, you may have found it difficult to find a good lot of collagenase from suppliers. If you’ve not experienced this in the past, you may wonder why this is happening now. Based upon my experience in collagenase product manufacture, and my interest in how business practices change over time, IRead more about 3 Factors may explain why you cannot find a “good lot” of collagenase[…]

What causes variation in the color of traditional collagenase products? Traditional collagenase products can range in color from a light tan to dark brown. Color is directly influenced by the collagenase manufacturing process. Collagenases and neutral proteases are the key enzymes in these products principally responsible for degrading extracellular matrix and in turn, releasing cellsRead more about Collagenase color: what does it tell you about product quality?[…]