Okay, let me explain for you non-biochemist computer guys what this means. Take a computer, break it down into the smallest possible parts you can. I'm not talking about the hard drive/motherboard/case level. I'm talking about the level of transistors, resistors, ICs, connectors, motors, and the little blue LED that blinks whenever your hard drive spins. Now catalog everything. Keep a record of what you found where, and how many you found (eg, you found a laser in the DVD drive but not in the motherboard). So now you have a parts list, and a good idea of what parts to expect where. If you start finding unexpected things in unexpected places (like a SCSI connector on your video card, or an audio out port on one of your DIMMs), that tells you something is wrong.
Take a look at the database entry for something common like glucose. It's got
- a brief, high-level description of the chemical
- details about the chemistry
- where it's found in the body
- details about how much of it was found in what parts of the body based on various studies that have already been done
- disorders it's linked to (eg, diabetes)
- where to go for more information
Now what's missing is a lot of information about the connections, so technically this isn't really a map (because it's missing relational data), but a catalog. We need to know how each chemical turns into another, and what does the conversion. It's kinda like having a complete parts list for the computer, but not knowing how most of the parts fit together, nor how many volts and amps to run through the wires. Some of these connections we already know. I have a very large poster on my wall illustrating the more common chemical pathways in various organisms. It's not nearly as complete as this catalog in terms of chemicals, but it's got a lot of connections.
The connections are what's really useful. To continue the computer analogy, if you know that the blue LED connects to the hard drive, then if you don't see the blue light blink, then there's probably something wrong with the hard drive. A significant number of drugs aren't active in the form that you take them. They become active when the body (usually in the liver) converts them from the delivery form to the active form. But some people, because of their genetic makeup, convert the drugs differently. They turn them into different metabolites. These metabolites might be totally inactive, or even toxic in some cases. So if you know the connecting system, you can put a drug in, look for what metabolites result, and determine whether or not that person should continue taking the drug.