We use purified hTSH (in PBS), but have issue with stability of the sample. Since the purified hormone is highly unstable the activity reduces drastically at room temperature. We had added BSA to the buffer but it causes hindrance in our immunoassay protocol.
We would like to know what other ways (buffers, additives) can be used to stabilize the hormone for use at room temperature?
Rohan Aggarwal , you should use preservative for diagnostic reagents, for example, ProClin 300 (0,1%). There are commercially available protein-free stabilizator
https://shop.surmodics.com/stabilzyme-protein-free-stabilizer-szpf-0050
Also you can use glycerol (to 50%), saharoze and caseine instead BSA
Antonina Kokisheva Can these stabilizers be used for hormones (small proteins around 30 kDa) without causing hindrance? Asking since many of them have written bovine as a source leading me to believe that they have albumin as a constituent.
Rohan Aggarwal, i amn't sure but i use it for small conjugates (5-10 kDa)
I didn't find information that StabilZyme® NOBLE Stabilizer (BSA-Free) containes albumin
Rohan Aggarwal Proclin 300 is antimicrobial and prevents the growth. Since thyroid hormones are proteins they will require stabilizers to keep them stable. Also add a zwitterionic detergent like CHAPS.
I agree with Antonina Kokisheva that there is no information available in regards to the composition of commercially buffers. But buffers from CANDOR and Surmodics does give good stability.
You can try PBS buffer with Methionine(100-300mM), Lysine(100-300mM), NaCl(50-200mM), EDTA(1-10mM), 1 to 2 % glycerol, Proclin- (0.01-0.1%) (*I also use BSA in this composition but you can try using it without BSA)
Do share the results in terms of stability.
All the best.
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