Book about biochemistry for physicist
Your question will probably get closed because any answer is going to be an opinion. Instead of recommending a book-I'll shed a little light on what your journey will be like.

The Subject(s)

Your pursuit to describe high level biological functionalities using first principals covers many fields. I don't think you'll find a single book that explains it all. Instead, you're going to have to learn from a number of different sources.


Physical Chemistry - This will give an overview of electronic structure using quantum mechanics
Physical Organic Chemistry - Learn how to apply physical chemistry to organic molecules.
Bio-Chemistry - Apply organic chemistry to biological processes.
Physical Bio-Chemistry Combines physical chemistry with bio chemistry.


You're really after point 4, but it will need to learn a fair amount before getting there.

The Reality

The reality of things is that we don't need to dig down to first principals to describe many biological processes. Chemistry is able to abstract enough of the nitty-gritty away to come up with easier &amp; faster high level concepts. 

Take programming for example, web developers don't need to write websites in assembly language because someone has gone ahead and abstracted it all into a nice user friendly language. You could spend a lifetime coding a site like stackexchange in assembly-or you could use a higher level language and do it in a few months.

Just how you won't find a book on website design using assembly language (first principals), you probably won't be finding one describing biology using pure quantum mechanics.

Further Steps

Assess your current knowledge of physical and (general) chemistry. Once you know which level you're at, go to different university sites and check which books the professors are using to teach. If you find a course that is covering the topics that you're interested in-contact the TA or professor and ask for recommendations; I'm sure they'd be happy to help.