I am using the Thermo Scientific DNase I (https://www.thermofisher.com/order/catalog/product/EN0521) to remove genomic DNA from RNA extracts eluted in nuclease free water.
The protocol calls for 1 u of DNase enzyme for 1µg of RNA, so a typical reaction would look like 8µL of sample, 1µL of 10x buffer, and 1µL of 1u of enzyme for a total rxn volume of 10µL. This protocol is typical for other DNase I treatment kits that I have come across.
Problem is, I have a handful of samples that are low concentration (i.e. less than 1µg of RNA in the suggested 8µL of sample). If i was using another kit, it seems like it is okay for DNase I enzyme to be in excess of the nucleic acids. However the brochure for this product has the line "Do not use more than 1 u of DNase I, RNase-free per 1 µg of RNA."
How should i proceed?
Should I just use 8µL of sample regardless?
Should I be tailoring the amount of enzyme i use to each reaction so the ratio of u enzyme to µg of sample is always less than 1? (if I do the second option do I need to adjust the amount of Buffer and EDTA as well?
Im inclined to go with option based on other results on the internet