Circular dichroism of bilirubin-amine heteroassociation complexes

✍ Scribed by David A. Lightner; Jing-Yi An

• Publisher: Elsevier Science
• Year: 1987
• Tongue: French
• Weight: 745 KB
• Volume: 43
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(01)90304-7

✦ Synopsis

Blchromophorlc (4315Z)-blllrubln-IXa, the yelloworange cy to toxic pigment of jaundice, adopts l lthtr of two intramolecularly hydrogen-bonded enantlomerlc conformations that are la dynamic equlllbrlum in solution. The tddltlon of S_(+)-2-aminobutane lndut$s, the+L;lr;Et,9e lutlons to exhibit intense bltlgnate circular dlchroltm [AE --26.0 (benzene)] of the blllrubln Long wavey&gth &-:lslbye? absorption band & J.B9the region -60,900 (benzene)]. At teen with terum albumin and other proteins, the opt??iLly tctlvt base acts as a chlral complexatlon agent to induct an l tymmetrlc trtnsformatlon of blllrubln, whose induced blslgnatt circular dlchrolsm Cotton effect is characteristic of txclton splitting of the component pyrromethenone chromophorts. D. A. LIGHTNW and J.-Y. AN Bilirubia ovee itr well-defined chiral tertiary structure (Fig. 1) in the crystal and non-polar rolvents to (i)zpariplanar conformations of the two pyrromathenone chromophorea, each poraeaaing Z-configuration carbon-carbon double bonds at C4 and Cls, -(ii) two propionic acid groups at C8 and Cl2 each capable of forming intramolecular hydrogen bond6 with the opposing pyrromathenone lac-