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J M Sodetz

Publications and source records attributed to J M Sodetz.

51 records · Page 3Linked to original sources
PubMed1980

Binding of the eighth component of human complement to the soluble cytolytic complex is mediated by its beta subunit.

The noncovalently associated alpha-gamma and beta subunits of the eighth component of human complement (C8) were isolated and examined for their ability to recombine to form C8. Each subunit was also examined to determine its capability to interact independently with the C8 binding site on the soluble form of the cytolytic complex of complement. Results indicate that alpha-gamma and beta physically recombine in solution to form native C8 when mixed in equimolar amounts, a finding consistent with the concomitant appearance of C8 hemolytic activity. The ability of each subunit to interact independently with SC5b-7, the precursor of the soluble cytolytic complex which binds C8, was determined by sucrose density gradient analyses. It was found that alpha-gamma exhibits little affinity for SC5b-7, while the beta subunit readily binds to yield a stable complex of SC5b-7(beta). Interaction of beta was specific for the C8 binding site on SC5b-7 as evidenced by the ability to compete with C8. Results indicate that structural domains which mediate specific interaction of C8 with the nascent cytolytic complex are located in the beta subunit of this unusual protein.

Complement C8↗
PubMed1978

Carbohydrate on human factor VIII/von Willebrand factor. Impairment of function by removal of specific galactose residues.

Human factor VIII/von Willebrand factor protein containing 120 +/- 12 nmol of sialic acid and 135 +/- 13 nmol of galactose/mg of protein was digested with neuraminidase. The affinity of native factor VIII/von Willebrand factor and its asialo form for the hepatic lectin that specifically binds asialoglycoproteins was assessed from in vitro binding experiments. Native factor VIII/von Willebrand factor exhibited negligible affinity while binding of the asialo derivative was comparable to that observed for asialo-alpha1-acid glycoprotein. Incubation of asialo-factor VIII/von Willebrand factor with Streptococcus pneumoniae beta-galactosidase removed only 62% of the galactose but abolished binding to the purified hepatic lectin. When the asialo derivative was incubated with purified beta-D-galactoside alpha2 leads to 6 sialyltransferase and CMP-[14C]NeuAc, only 61% of the galactose incorporated [14C]NeuAc. From the known specificites of these enzymes, it is concluded that galactose residues important in lectin binding are present in a terminal Gal/beta1 leads to 4GlcNAc sequence on asialo-factor VIII/von Willebrand factor. The relative ristocetin-induced platelet aggregating activity of native, asialo-, and agalacto-factor VIII/von Willebrand factor was 100:38:12, respectively, while procoagulant activity was 100:100:103.

Animals↗
PubMed1976

Streptokinase.

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Amino Acids↗
PubMed1975

The mechanism of activation of rabbit plasminogen by urokinase.

The data presented in this paper show that when rabbit plasminogen is activated to plasmin by urokinase at least two peptide bonds are cleaved in the process. Urokinase first cleaves an internal peptide bond in plasminogen, leading to two-chain disulfide-linked plasmin molecule. The plasmin heavy chain of molecular weight 66,000 to 69,000 possesses an NH2-terminal amino acid sequence identical with the original plasminogen (molecular weight 88,000 to 92,000). The plasmin light chain of molecular weight 24,000 to 26,000 is known to be derived from the COOH-terminal portion of plasminogen. The plasmin generated during the activation of plasminogen is capable, by a feedback process, of cleaving a peptide of molecular weight 6,000 to 8,000 from the NH2 terminus of the heavy chain, producing a proteolytically modified heavy chain of molecular weight 58,000 to 62,000. Plasmin also can cleave this same peptide from the original plasminogen, yielding an altered plasminogen of molecular weight 82,000 to 86,000. This plasmin-altered plasminogen and the plasmin heavy chain derived from it by urokinase activation process NH2-terminal amino acid sequences which are identical with each other and with the plasminolytic product of the original plasmin heavy chain. These studies support a mechanism of activation of plasminogen by urokinase which involves loss of a peptide located on the NH2 terminus of plasminogen. However, these same results show that this NH2-terminal peptide need not be released from rabbit plasminogen prior to the cleavage of the internal peptide bond which leads to the two-chain plasmin molecule. Furthermore, these studies show that urokinase cannot remove this peptide from either the original rabbit plasminogen molecule or from the heavy chain of the initial plasmin formed.

Amino Acid Sequence↗