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> why they couldn't just measure bradykinine levels directly? Is that too hard? It is. To measure gene expression, you isolate total mRNA and sequence it. Th
by 08-15 6y ago
> why they couldn't just measure bradykinine levels directly? Is that too hard?
It is. To measure gene expression, you isolate total mRNA and sequence it. This tells you the expression of all genes simultaneously. The protocol is fairly standard, cheap, and quick. That doesn't tell you anything about bradykinine, though, because there is no mRNA that codes for it.
In contrast, no such protocol exists for proteins. Sequencing a single protein is comparatively difficult, and no high throughput device exists that sequences lots of proteins, let alone quantifies their abundance. The traditional lab methods like PAGE gels are slow and labor intensive.
- robwwilliams 6y agoThis comment on quantitative protein assays is only partly correct. It is definitely harder than quantitative assays of messenger RNA (aka “gene expression” and not as comprehensive. But there are now hundreds of quantitative proteomic studies that survey 5000 or more proteins in single samples (and their peptide fragments). Search PubMed for the author “Aebersold R”.
- AnthonBerg 6y agoThank you for a great comment!, the crisp context is a good gateway for further reading. Could I ask you for any hints about where/how to learn more? And/or if there's a way to follow your work online?