Lysine and arginine are both positively charged amino acids that are mostly present on protein surfaces. There are several differences between lysine and arginine. 

Lysine

• Is a basic amino acid that cannot be synthesized by the human body and is hence an essential amino acid
• Is encoded by codons AAA and AAG
• Has a lysyl side chain
• Provides less stability to proteins because of its geometric structure
• Forms fewer electrostatic interactions in proteins and in one direction only
• pKa value of side chain is 10.54
• Functions – plays a role in proteinogenesis and in epigenetic histone modifications, and helps in the production of carnitine and in crosslinking of collagen polypeptides and uptake of essential minerals 

Arginine

• Is a basic amino acid that can be synthesized in the human body and is hence considered a semi-essential or non-essential amino acid 
• Is encoded by codons CGA, CGC, CGG, CGU, AGA, and AGG
• Has a side chain consisting of a 3- carbon aliphatic straight-chain ending in a guanidino group
• Provides more stability to proteins because of its geometric structure
• Forms a larger number of electrostatic interactions in proteins in three possible directions
• pKa value of side chain is 12.48
• Functions – is the precursor for the biosynthesis of nitric oxide