0 a chemical bond in which two atoms share one or more pairs of electrons that hold them together -- 共價鍵（原子間共用電子而形成的化學鍵）
This structure is unique in enzymes in that the two ends are the only form of covalent bond attachment to rest of the protein.
Thereafter, b-ionone freely exchanged within the binding pocket during perfusion because the truncated retinoid cannot form a covalent bond with opsin.
The mechanism of the attractive force in a covalent bond relies on highly complex electromagnetic interactions between electrons with magnetic spin components.
This is of course equivalent to saying that as a covalent bond begins to form between the phosphorus and the 2h-oxygen, the burden of the negative charge becomes relieved.
This type of chemical bond is either a non-polar covalent bond or a polar covalent bond.
As such, the chemical linkage (usually a covalent bond) should be subjectable to biodegradation, such as hydrolysis, by an enzymatic or non-enzymatic mechanism.
What makes the isopeptag different from other peptide tags is that it can bind its binding protein through a permanent and irreversible covalent bond.
If the unpaired electrons can spin-pair to form a covalent bond, then the covalent bonding interaction can lower the energy of the charge transfer state.
