Purified placental protein

The Biological Characterization of Purified Placental Protein (Human) [PPP(H)]... 

Poly(ADP-ribose) synthetase is a chromatin-bound enzyme which, in the presence of DNA, catalyzes polymerization of the ADP-ribose moiety of NAD to form a protein-bound homopolymer, poly(ADP-ribose) (1). The enzyme is automodified during the reaction. It has been shown that the enzyme consists of three functional domains for DNA-binding, automodification, and NAD-binding (2-4). The enzyme has recently been purified from human placenta and characterized (4, 5). To study the structure and function of the enzyme in more detail we have prepared monoclonal antibodies to the placental enzyme (6, 7). The present study defines three monoclonal antibodies to human poly(ADP-ribose) synthetase and shows that one of the antibodies which binds to the NAD binding domain inhibits the enzyme activity. 

Fig 1. Affinity chromatography of the RBP receptor on RBP-affinity resin. The RBP-receptor was purified from an octyl-glucoside extract of human placental membranes (120 mg of protein) using an RBP-Gel 6X affinity matrix Arrows indicate the stages at which various buffers (A-D) were introduced to the resins The compositions of the buffers are described in the Subheading 2. 

The hepatic 31 kDa a-TTP is a cytosolic protein that has been purified and found to exist as two charge isoforms (Kuhlenkamp et al, 1993). The primary structures of a-TTP from rat liver (Sato et al, 1993) and human liver (Arita et al, 1995) have been determined and found to have a structural homology with retinaldehyde-binding protein (Sato et al, 1993). It is now known that a defect in a-TTP is the cause of ataxia (a nervous disorder characterized by the inability to coordinate muscular movement) associated with familial isolated vitamin E deficiency (Traber etal, 1990c Schuelke etal, 1999). Recent work also indicates that a-TTP is very important for the normal development of placental labyrinthine trophoblasts the placenta of female mice deficient in a-TTP was found to be extremely impaired and the embryos died at mid-gestation (Jishage et al, 2001). 

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