Is the imported M-MLV reverse transcriptase currently out of stock? Seeking alternatives

When substituting, don't just look at enzyme activity units. First confirm whether it is RNase H minus, whether it has been validated by qPCR or reverse transcription of total cellular RNA, and whether the buffer contains DTT. For 20 μL/1 μg of total cellular RNA, this is a conventional scale, and most domestic M-MLV mutants can handle it. You can ask the manufacturer to provide comparative Ct or electrophoresis data, and perform a before-and-after comparison using your own RNA across 10 samples.

The monthly consumption of 3-4 units is not large. It is recommended to choose two domestic alternatives and try them out separately to lock in one long-term supplier. Ask about delivery time, availability of stock, cold chain, and after-sales technical support. No matter how suitable the price is, it also depends on the stability between batches. It is best to ask the supplier to provide quality reports for recent batches. Do not make significant changes to the original reverse transcription system just because of stock shortage, as the risk of replacing enzymes of the same type is minimal.

If it is urgent and bulk enzymes are difficult to find, consider using 2 x reverse transcription premix. The single cost may be lower, and most premix already contains RNA enzyme inhibitors, reducing the risk of cap opening and packaging contamination. It is recommended to first purchase small packaging or trial packaging to run a batch of samples, focusing on comparing Ct values, amplification curves, and negative controls, without pursuing the same brand replacement.

When there is a shortage of imported goods, you can first ask the agent to check the national inventory, and some regions may still have stock available. At the same time, it is recommended to directly contact the domestic manufacturer or general agent to apply for a trial installation. The 2000U M-MLV RNase H minus is usually priced in the range of a few hundred yuan per unit, and there is room for choice within a budget of 800 yuan. Special attention should be paid to requesting COA and inter batch difference data to avoid comparing only U numbers.