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OK a bit annoying here... My Ubuntu 9.10 has this iBus input method that I could never get it to work nicely. I will try my best to explain the 'enzyme cycling'.
*** What.
Enzyme cycling is a technique where you add enzymes to the assay system to 'amplify' a product from a certain enzymatic reaction.
*** Why.
In some cases, the researcher wants to detect a certain substance which is naturally in very low concentration. In addition this substance is hard to enrich. The concentration is too low to be detected under normal enzymatic sensitivity.
So it comes with the idea of the enzyme cycling. Let's say you want to detect the substrate S1.
Enzyme A uses S1 to produce P1. P1 can be coupled into a colormetric assay by enzyme B, generating P2 and P3 as product. The P2 is used up by Enzyme C to generate a colormetric signal. The P3 is used by Cycling Enzyme CE1, CE2 and perhaps CEn to regenerate P1. Hence the P1 goes to the cycle again and again.
*** How.
If one can image how the PCR works here, it is easier to understand. The principle of using RT-PCR to semi-quantify the template in the system is that, the yield of the PCR at some stage depends on the template concentration. That is how you can use RT-PCR to compare redundancy of the RNA in different samples.
*** Complication. Keep in mind that, like the RT-PCR or realtime PCR, one would need to establish the curve. i.e., to what concentration the detection of the substrate would be in the linear range of the assay. Also because there are lots of enzymes in the system, one has to investigate that any components in the system is not an inhibitor of all the enzymes, or if it is, the effect should be minimum. In other words the whole system needs to be optimized so that the rate-limiting step is the process of your target reaction.
For reference, there is a review but I do not have access to it. If anybody can upload that that would be great.
Here are the two references including the review.
cuturl('http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6T57-48PDJWH-1&_user=947884&_coverDate=07%2F01%2F2003&_rdoc=1&_fmt=high&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1189284914&_rerunOrigin=google&_acct=C000047720&_version=1&_urlVersion=0&_userid=947884&md5=d2ee2b9721f092b1a0cb301a847aa544')
cuturl('http://www.springerlink.com/content/mt331267127k7wk2/')
Please do not hesitate to correct me if you find any mistakeSmile I have not read this in great detail. Just find it interesting and want to share with you here.
