Neuroscience book recommendations
I don't have enough rep yet to comment on your question, but I have read the whole of Kandel's Principles of Neural Science in 2nd year of med school (last year) and I thoroughly enjoyed all of it!

I would recommend Part II: Cell and Molecular Biology of the Neuron to you, as this is where most detailed discussion about the molecolular structure of membrane proteins etc. is happening. And that's only about 110 pages. It probably doesn't go as far as what you are looking for, but I found it a very good introduction to the field of ion channels and how they work. The rest of the book is very interesting if you are keen to get a thorough overview of the whole field of neural science, but you won't find too much detail on the biochemical level there. Part III: Synaptic Transmission with about 150 pages is also a very good read. 

For a specific focus on biochemistry you'll have to look for another book, but quite likely you'll find good candidates in the Selected Readings at the end of each chapter, here is one example of those lists from chapter 7: