Session: ACS Award for Encouraging Women into Careers in the Chemical Sciences: Symposium Honoring Katherine Franz :

Riboflavin Binding Protein (RBP) is a crucial transport protein in oviparous species, responsible for the delivery of the essential vitamin riboflavin to the oocyte. Additionally, RBP has been observed to bind copper in a 1:1 molar ratio in vitro. Determination of the binding constant of RBP for copper is complicated by simultaneous reduction of a significant portion of the copper by an unknown reducing agent upon protein binding. Ongoing efforts in our lab to deconvolute the binding event using a combination of electrochemical and physical measurements will be presented. In particular, we have applied Isothermal Calorimetry (ITC) and cyclic voltammetry (CV). We compare the interaction with copper by apo- and holo- RBP (riboflavin free or bound) in the presence and absence of the oxidizing agent nitrate.

The primary known mineral storage system in avian embryos is the vitellogenin/lipovitellin/phosvitin protein system. Phosvitin and lipovitellin are the products of vitellogenin decomposition and RBP gains access to the oocyte via the vitellogenin receptor. ITC data shows that there is a previously unobserved interaction between RBP and phosvitin. We explore the role of RBP as a possible vehicle for delivery of copper to phosvitin by FPLC, graphite furnace AA, ITC and CV.

Marilee Benore

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