This is actually a mixture of two topics – Protein metabolism and Nucleotide metabolism. Individually both are small topics so many authors write this in a single section of Nitrogen metabolism.
1. Amino Acids Metabolism
Here at the starting of this chapter I have shared 2 videos. Watch one of them based on whatever teaching style you are comfortable with.
2. Urea Cycle
For the Urea cycle, I am sharing 2 videos. The first one is a long video that covers the basics but if you are clear with the details already and just want to brush up then the second video by shomu’s biology is the one you need.
3. PORPHYRIN METABOLISM (Heme Metabolism)
I wanted to touch on porphyrin metabolism but we can’t just study it separately so I am here sharing 2 videos. The first video is a brief video on porphyria and heme metabolism, but the second one is a much better video explaining heme metabolism in-depth.
4. Nucleotide Metabolism
There are many lectures available on this topic. I am sharing just the one relevant at this level. If you want more details then refer to MIT-OCW.
Here I have shared 1 complete lecture on Nucleotide metabolism by Ninja Nerd. The other one is a playlist of topicwise videos of the same topic.