In {TAIL ~ some embodiments} of the methods, a mixture comprising {HEAD ~ a sample} and a substrate for the enzyme is provided 
In { TAIL ~ some embodiments } of the methods , a mixture comprising { HEAD ~ a sample } and a substrate for the enzyme is provided
OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH