Ligands naturally occurring

Besides classical receptor classes that bind endogenous or naturally occurring ligands and act via prototypical intracellular signaling cascades, a considerable number of transmembrane proteins are referred to as receptors albeit their natural ligands are unknown or they do not... 

Giesy JP (1980) Cadmium interactions with naturally occuring ligands. In Nriagu JC (ed) Biogeochemistry of cadmium, pt. 1. Wiley, New York, pp 237-256... 

Meier B. (1995). Passiflora incarnata L.—Passion flower. Zeitschrift fur Phytotherapie. 16(2) 115-26. Medina JH, Paladini AC, Wolfman C, Levi de Stein M, Calvo D, Diaz LE, Pena C. (1990). Chrysin (5,7-di-OH-flavone), a naturally-occurring ligand for benzodiazepine receptors, with anticonvulsant properties. Biochem Pharmacol. 40(10) 2227-31. 

The more than 100-strong family of mammalian receptor tyrosine kinases can be divided into different subfamilies, which are named according to their naturally occurring ligands (Fantl et al., 1993). The subfamilies are classified according to the structure... 

Most studies of zinc complexes of amino acids have concentrated upon naturally occurring ligands, but some other amino acids have been investigated. Complexes with 3- and 4-aminobenzoic acids have been reported247,248 and a crystal structure of [ZnL2]-1.5H20 (HL = 4-aminobenzoic acid) has shown that the compound is polymeric, with the metal in a distorted N202 environment.248... 

The reader is referred to other chapters for the following heterocyclic systems ligands with mainly amine-type groups and one heterocyclic substituent (Chapter 13.1) polypyrazolyl compounds (Chapter 13.6) ligands that also contain another donor atom, such as O, S or P (Chapters 14, 20.3 and 20.4) macrocyclic ligands (Chapter 21) and naturally occurring ligands, such as histidine (Chapters 22 and 62). 

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