scholarly journals Purification of the human complement control protein C3b inactivator

1980 ◽  
Vol 191 (1) ◽  
pp. 173-182 ◽  
Author(s):  
L G Crossley ◽  
R R Porter
Keyword(s):  
Prolonged Storage ◽  
Freezing And Thawing ◽  
Ph Optimum ◽  
Complement Control Protein ◽  
Alpha Chain ◽  
Inactive Form ◽  
Activation Products ◽  
A Cell ◽  
Control Protein

An alternative method of isolation from human plasma is described for C3b inactivator, C3bINA, the proteinase that in conjunction with either beta 1H or C4b-binding protein will hydrolyse respectively C3b or C4b, the activation products of the third, C3 and fourth, C4, components of complement. The purification is by chromatography of plasma on columns of QAE-Sephadex, wheat-germ agglutinin-Sepharose, hydroxyapatite and Sephacryl S-200. The yield of C3bINA (6 mg from 500ml of plasma) is severalfold higher than in previously described methods. The sensitivity of the assay for C3bINA has been increased by including optimal amounts of beta 1H, and it was observed that beta 1H was essential for hydrolysis by C3bINA of C3b, whether the C3b was in solution or bound to a cell surface. Native C3 is not hydrolysed by C3bINA + beta 1H, but the haemolytically inactive form that appears on prolonged storage at 4 degrees C or on freezing and thawing is hydrolysed and gives fragments of the alpha-chain of 75000 and 43000 apparent mol.wt. As the alpha'-chain of C3b, which has lost an N-terminal peptide C3a, gives fragments of 67000 and 43000 apparent mol.wt. when incubated with C3bINA + beta 1H, this suggests that the larger fragment is N-terminal and the smaller one C-terminal. The pH optimum of C3bINA with soluble substrates is 6.0, but no clear classification of the type of proteinase to which this enzyme belongs has been obtained.

THE MECHANISM OF THE ACID ACTIVATION OF RABBIT UTERINE RENIN

1979 ◽  
Vol 92 (4) ◽  
pp. 720-730 ◽  
Author(s):  
Jørgen Jørgensen
Keyword(s):  
Proteolytic Enzymes ◽  
Pressor Response ◽  
Gel Filtration ◽  
Acid Activation ◽  
Freezing And Thawing ◽  
Ph Optimum ◽  
Active Renin ◽  
Inactive Form ◽  
Repeated Freezing ◽  
Rate Of Activation

ABSTRACT Besides active renin an inactive form of renin could be demonstrated in uterine tissue. On gel filtration it was eluted as a molecule of slightly higher molecular weight than active renin, and it could be irreversibly activated by acidification at 37°C. The activation had a pH optimum between pH 3.8 and pH 5.3. Acid activated uterine renin was found identical to active uterine renin by 1) the formation of angiotensin I with time after addition of rat substrate, 2) the pressor response in the rat, 3) neutralization by antirenin and 4) similar Michaelian constants. Repeated freezing and thawing, acidification at 4°C and dialysis against 4 mol/l NaCl did not give any activation. A lower rate of activation of diluted samples and activation by trypsin at pH 7.4 suggest that proteolytic enzymes are involved in the activation.

scholarly journals Disabling complement regulatory activities of vaccinia virus complement control protein reduces vaccinia virus pathogenicity

Vaccine ◽  
2011 ◽  
Vol 29 (43) ◽  
pp. 7435-7443 ◽  
Author(s):  
John Bernet ◽  
Muzammil Ahmad ◽  
Jayati Mullick ◽  
Yogesh Panse ◽  
Akhilesh K. Singh ◽  
...  
Keyword(s):  
Vaccinia Virus ◽  
Complement Control Protein ◽  
Control Protein

Enzymatic Synthesis of 1-Sinapoylglucose from Free Sinapic Acid and UDP-Glucose by a Cell-Free System from Raphanus sativus Seedlings

1980 ◽  
Vol 35 (3-4) ◽  
pp. 204-208 ◽  
Author(s):  
Dieter Strack
Keyword(s):  
Phenolic Acids ◽  
Enzymatic Synthesis ◽  
Raphanus Sativus ◽  
High Performance ◽  
Sinapic Acid ◽  
Carboxyl Group ◽  
Ph Optimum ◽  
Free System ◽  
Sh Group ◽  
A Cell

Abstract Protein extracts from seedlings of Raphanus sativus catalyze the transfer of the glucosyl moiety of UDP-glucose to the carboxyl group of phenolic acids. Enzymatic activity was determined spectrophotometrically by measuring the increase in absorbance at 360 nm and/or by the aid of high performance liquid chromatography (HPLC). From 12 phenolic acids tested as acceptors, sinapic acid was by far the best substrate. The glucosyltransfer to sinapic acid has a pH optimum near 7 and requires as SH group for activity, p-Chloromercuribenzoate (PCMB) inhibits activity, which can be restored by the addition of dithiothreitol (DTT). The formation of 1-sinapoylglucose was found to be a reversible reaction, since the addition of UDP results in a breakdown of the ester.

scholarly journals ISOZYMES OF ACID PHOSPHATASE IN NORMAL AND CALMETTE-GUÉRIN BACILLUS-INDUCED RABBIT ALVEOLAR MACROPHAGES

1968 ◽  
Vol 128 (5) ◽  
pp. 1031-1048 ◽  
Author(s):  
S. G. Axline
Keyword(s):  
Acid Phosphatase ◽  
Phosphatase Activity ◽  
Alveolar Macrophages ◽  
Acid Phosphatase Activity ◽  
Enzyme Inhibitors ◽  
Freezing And Thawing ◽  
Ph Optimum ◽  
Lysosomal Fraction ◽  
Repeated Freezing ◽  
Major Acid

The acid phosphatase activity of normal alveolar and BCG-induced alveolar macrophages has been examined. Five electrophoretically distinct forms of acid phosphatase have been identified in both normal and BCG-induced macrophages. The acid phosphatases can be divided into two major categories. One category, containing four distinct forms, is readily solubilized after repeated freezing and thawing or mechanical disruption The second category, containing one form, is firmly bound to the lysosomal membrane and can be solubilized by treatment of the lysosomal fraction with Triton X-100. The Triton-extractable acid phosphatase and the predominant aqueous soluble acid phosphatase have been shown to differ in the degree of membrane binding, in solubility, in net charge, and in molecular weight. The two pre-dominant phosphatases possess identical pH optimum and do not differ in response to enzyme inhibitors. BCG stimulation has been shown to result in a nearly twofold increase in acid phosphatase activity. A nearly proportionate increase in the major acid phosphatase forms has been observed.

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