Theoretical study of copper binding to GHK peptide ScienceDirect Is Less More? Influence of the Coordination Geometry of Copper(II) Picolinate Chelate Complexes on Metabolic Stability Inorganic Chemistry Theoretical study of copper binding to GHK peptide ScienceDirect GHK Cu as a multifunctional copper peptide: synthesis routes, process engineering and emerging applications Systems Microbiology and Biomanufacturing Springer Nature Link