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I'm trying to dissociate a tumor, and most protocols like NCI/NIH recommend a 10X triple enzyme digestion stock consisting of: collagenase type IV, DNase I type IV and hyaluronidase type V in HBSS. This goes all the way back to the 90s, and the recipe varies between papers (dispase, papain, neutral protease, elastases, etc.). The so-called official recipe that I've been tasked to use is composed of the above, however, mostly from Sigma-Aldrich (C5138, D5025, H6254)

I can't really find anything that says what the real differences are between these types of enzyme are, however. Or why for example type IV DNase works better than type II, and so forth. Is it perhaps that the recipe just happened to stick?

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It’s years since I looked at a Sigma catalogue (before it became Sigma-Aldrich) but as I remember, these designations are arbitrary proprietary ones used by Sigma to distinguish different sources — the key point being that Sigma didn’t generally manufacture all of these themselves, but obtained the from third parties.

The other point to note is that these enzyme preparations were/are generally impure, but to differing extents, so the type designations allowed you to re-order a particular preparation that worked, and also to specify the actual grade you used when you published so that other people could repeat your work. More expensive grades would, no doubt, also work in the sort of crude application you describe, but they would be a waste of money.

I thought the catalogues used to give you some information (organism/tissue at least), but, as I said, it’s been a long time (although be careful with your “way back to the ’90s”, young man).

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  • $\begingroup$ Regardless of your age, 17 years is a fairly significant amount of time. Old fart. $\endgroup$ – MattDMo Aug 22 '16 at 18:28
  • $\begingroup$ This is kind of what im getting out of their catalog. I saw one source that said something like DNase IV works better on DNA containing lots of repeats, but I couldn't find anything else to back that up. Cost vs. activity/purity seems to be the case. $\endgroup$ – CKM Aug 22 '16 at 20:35
  • $\begingroup$ And to be fair, reading "Cancer Research 54" circa 1994 is a bit like reading a history book about T cell-based therapies. $\endgroup$ – CKM Aug 22 '16 at 20:36
  • $\begingroup$ But there's some stuff of that vintage and earlier that has hardly been added to since, especially in very chemical areas. I was trying to find info (for a SE Biology question) on sugar ring conformation in different helices and had to walk over to the library to get a book published in the 80s. $\endgroup$ – David Aug 22 '16 at 20:58

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