Adrenal glands are one of the pivotal glands of the human endocrine system. Recently, the extracellular matrix (ECM) of the adrenal capsule and cortex was explored in two fractions: outer fraction (OF) and inner fraction (IF). A significant variation in the ECM proteins' levels, including collagens, was documented. Collagen undergoes a plethora of post-translational modifications (PTMs), exhibiting crucial roles such as cell-matrix interaction and cross-linking. However, the site-specific identi