PDPH

PDPH is soluble in 0.1 M sodium acetate, pH 5.5, at a maximal concentration of 14.2 mg/ml. The reagent is particularly stable in acetonitrile for preparation of concentrated stock solutions. 

PDPH has been used in the preparation of immunotoxin conjugates (Zara et al., 1991). It has also been used to create a unique conjugate of nerve growth factor (NGF) with an 

PDPH also may be used as a thiolation reagent to add sulfhydryl functional groups to carbohydrate molecules. The reagent can be used in this sense similar to the protocol described for AMBH (Chapter 1, Section 4.1). After modification of an oxidized polysaccharide with the hydrazide end of PDPH, the pyridyl group is removed by treatment with DTT, leaving the exposed sulfhydryl (Fig. 169). 

PDPH has been used in the preparation of immunotoxin conjugates (Zara et al., 1991). It has also been used to create a unique conjugate of NGF with an antibody directed against the transferrin receptor OX-26, which could traverse the blood-brain barrier (Friden et al., 1993). Labeling of antibody molecules with PDPH at oxidized polysaccharide sites followed by reduction to free the sulfhydryl has been used to form a technetium-99m complex for radiopharmaceutical use (Ranadive et ah, 1993) (Chapter 8, Section 2.5). 

---

Pd(2-pyN=CNCH=CHCH=CH)2,1, 423 PdC20H18N3 [PdPh(dien)]+, 5,1116 PdC20H18N6... 

Figure 5.14 PDPH reacts with thiol-containing compounds through its pyridyl disulfide end to form reversible disulfide linkages. Its hydrazide end then may be subsequently conjugated with an aldehyde-containing molecule to form hydrazone bonds. Glycoproteins may be crosslinked using this approach after periodate activation to...

Figure 5.15 PDPH may be used to add a sulfhydryl group to an aldehyde-containing molecule. After reacting its hydrazide end with the aldehyde to form a hydrazone bond, the pyridyl disulfide may be reduced with DTT to create a free thiol.

Figure 10.3 Antibody molecules oxidized with sodium periodate to create aldehyde groups on their polysaccharide chains can be modified with PDPH to produce thiols after reduction of the pyridyl disulfide. Direct labeling of the sulfhydryls with "Tc produces a radioactive complex.

W-(2-Aminoethyl)-l,2-diaminoethane (dien) yields complexes [PdX(dien)]X (X = Cl or I) 204,20s a range of solvated complexes may be obtained by reaction of [Pdl(dien)] with AgC104 in the appropriate solvent. As for the platinum analogue, the aqua complex [Pd(dien)(H20)](C104)2 reacts with tetraphenylborate to yield [PdPh(dien)](BPh4). Reaction of the hydroxo complex with carbon monoxide yields C02 and palladium metal is deposited.206... 

---