Vol . 16, No . 5

Conference Abstracts

PF/dil and PF/n~t of Miles and Wilhelm in their characteristics of activationand inhibition . The results suggest that (A) PF/dil and PRA are identical aub-stancea and (B) DE may be plasma kallikrein bound to alpha-2~macroglobulin(a-2-M) . Activities of PRA and DE are expressed as cpm 3H-CH30H released from3H-tosylarginine methyl ester.

The following results were reported : 1) Plasmas deficient in Hageman fac-tor or Fletcher factor showed no or slight activities for both PKA and DE .2) On the other hand, plasma deficient in C1-esterase inhibitor gave higherthan normal values for both enzymes . 3) Electrophoretic analyses on polyacryla-mide gels showed that the major peak of activity for PKA.was found in the al-bumin region, while that for DE was in the globulin region . 4) Inhibitors ofHageman factor activation such as hexadimethrine bromide (100 ug/ml) and sper-mine (500 ug/ml) inhibited the generation of PKA.

Further studies indicated that plasma stored in hexadimethrine bromide-coated tubes or polyethylene tubes generated only small amounts of DE . Soybeantrypain inhibitor (SBTI), if added before the glass contact, inhibited the generation of DE, but did not inhibit the DE after its formation . Acid treatmentof plasma, similar to that used to inactivate a-2-M, increased DE generation,but this esterase could now be inhibited by SBTI . A decrease in the prekalli-krein content of the plasma was found after generation of DE . No kinin wasformed when DE was incubated with high molecular weight bovine kininogen, Thuea close relationship is assumed between DE and PF/net, but the nature of thebiological permeability increasing activity is open to question .

(These studies have been reported in part in Fed . Proc ., 32, 846 Aba .,(1973) and Biochem . Pharm., 24, in press) .

THE RELATION BETWEEN SURFACE FACTOR AND PERMEABILITY FACTOR

Brenda Mason

The Lister Institute of Preventive MedicineChelsea Bridge Road, SW1W BRH, Englaad

785

Surface factor (SF) is adsorbed to the glass and permeability factor(PF/dil) is generated in solution when normal human plasma is diluted in glassvessels . At 20° SF was removed from dilute plasma by adsorbing with quantitiesof glass ballotini. The adsorbed dilute plasma, though free of SF, retainedits capacity to increase vascular permeability and to activate the kinin system .Similar quantities of SF were adsorbed to ballotini when dilute plasma wastreated at 3° . The cold-adsorbed plasma dilution when examined at 20° had noactivity, and none was generated by glass . But it developed prekininogenaseactivator and permeability-increasing activity, similar in potency to that ofplasma adsorbed at 20° , when rotated with ballotini previously coated withdilute plasma . As the reaction of SF with pre PF/dil, but not with glass, istemperature dependent, it is likely that SF is an enzyme or complex of enzymes,but its attachment to glass does not entail an enzyme reaction . Since activeSF is separable from pre PF/dil, this finding suggests that PF/dil is not theactivator fragment of adsorbed Hageman factor, unless SF contains a proportionof the total PF/dil, leaving the remainder in solution .