scholarly journals Activation of the first component of human complement (C1) by antibody—antigen aggregates

1978 ◽  
Vol 175 (2) ◽  
pp. 383-390 ◽  
Author(s):  
A W Dodds ◽  
R B Sim ◽  
R R Porter ◽  
M A Kerr
Keyword(s):  
Conformational Change ◽  
Proteolytic Activity ◽  
Maximum Rate ◽  
Catalytic Site ◽  
The Other ◽  
Peptide Chain ◽  
Human Complement ◽  
Rate Of Activation

The activation of subcomponents C1r and C1s in the first component of complement, C1, when bound to antibody-antigen complexes was investigated. Activation was followed both by the splitting of the peptide chains of subcomponents C1r and C1s and by the development of proteolytic activity. For the maximum rate of activation to occur, all components must be present in approximate molar proportions of antibody: C1q:C1r:C1s of 13:1:5:5. For activation of subcomponent C1s, subcomponents C1r or C1r, but not C1r inactivated with iPr2P-F (di-isopropyl phosphorofluorideate), are effective. For activation of subcomponent C1r, subcomponents C1s, C1s or C1s inactivated with iPr2P-F are effective. Subcomponent C1s is activated by C1r, and C1r is activated autocatalytically, probably through the formation of an intermediary C1r. in which the peptide chain is unsplit but a conformational change caused by interaction with the other components has led to the formation of a catalytic site able to split subcomponent C1r to C1r.

scholarly journals Ligand-specific conformational change drives interdomain allostery in Pin1

2021 ◽  
Author(s):  
Beat Vogeli ◽  
Alexandra Born ◽  
Janne Soetbeer ◽  
Morkos Henen ◽  
Frauke Breitgoff ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Ligand Binding ◽  
Conformational Change ◽  
Conformational Changes ◽  
Catalytic Domain ◽  
Catalytic Site ◽  
The Other ◽  
Allosteric Mechanism ◽  
Catalytic Loop ◽  
Extended States

Abstract Pin1 is a two-domain cell regulator that isomerizes peptidyl-prolines. The catalytic domain (PPIase) and the other ligand-binding domain (WW) sample extended and compact conformations. Ligand binding changes the equilibrium of the interdomain conformations, but the conformational changes that lead to the altered domain sampling were unknown. Prior evidence has supported an interdomain allosteric mechanism. We recently introduced a magnetic resonance-based protocol that allowed us to determine the coupling of intra- and interdomain structural sampling in apo Pin1. Here, we describe ligand-specific conformational changes that occur upon binding of pCDC25c and FFpSPR. pCDC25c binding doubles the population of the extended states compared to the virtually identical populations of the apo and FFpSPR-bound forms. pCDC25c binding to the WW domain triggers conformational changes to propagate via the interdomain interface to the catalytic site, while FFpSPR binding displaces a helix in the PPIase that leads to repositioning of the PPIase catalytic loop.

Filtration by superficial and deep glomeruli of normovolemic and volume-depleted rats

1986 ◽  
Vol 250 (1) ◽  
pp. F86-F91
Author(s):  
R. V. Pinnick ◽  
V. J. Savin
Keyword(s):  
Basement Membrane ◽  
Maximum Rate ◽  
Rate Of Change ◽  
The Other ◽  
Membrane Area ◽  
Morphometric Analyses ◽  
Three Samples ◽  
Glomerular Size ◽  
Glomerular Ultrafiltration

We measured glomerular ultrafiltration coefficient (Kf) of isolated superficial (S) and deep (D) glomeruli of normovolemic and volume-depleted rats. Filtration was induced in vitro, and Kf was calculated from the maximum rate of change in glomerular size. Basement membrane area (A) for each glomerulus was estimated from morphometric analyses, and glomerular capillary hydraulic conductivity (Lp) was calculated by the formula Lp = Kf/A. Kf of S and D glomeruli of normovolemic rats were 2.98 +/- 0.98 and 4.25 +/- 0.07 nl . min-1 . mmHg-1, respectively. In hypovolemic rats, Kf of S glomeruli fell by approximately 50% to 1.52 +/- 0.14 nl . min-1 . mmHg-1 (P less than 0.001), whereas Kf of D glomeruli remained unchanged at 4.28 +/- 0.10 nl . min-1 . mmHg-1. Lp, calculated using the peripheral capillary area, averaged 1.98 +/- 0.09 and 1.98 +/- 0.06 microliter . min-1 . mmHg-1 . cm-2 in S and D glomeruli of normovolemic rats and 1.89 +/- 0.11 microliter . min-1 . mmHg-1 . cm-2 in D glomeruli of hypovolemic rats. Lp of S glomeruli of volume-depleted rats (0.90 +/- 0.03 microliter . min-1 . mmHg-1 . cm-2) was lower than in any of the other three samples. Mild hypovolemia causes the Kf of S glomeruli to decline, whereas Kf of D glomeruli remains constant. The decrease in Kf occurs without an alteration in capillary area and is most likely due to a decrease in Lp.

scholarly journals Effects of Imprinting and Water Activity on Transesterification and Thermostability with Lipases in Ionic Liquid

2021 ◽  
Vol 35 (1) ◽  
pp. 57-63
Author(s):  
M. Matsumoto ◽  
K. Nakao ◽  
Y. Tahara
Keyword(s):  
Ionic Liquid ◽  
Water Content ◽  
Benzyl Alcohol ◽  
Vinyl Acetate ◽  
Water Activity ◽  
Maximum Rate ◽  
The Other ◽  
Organic Media ◽  
Catalytic Activities ◽  
Michaelis Constants

The effect of bio-imprinting and water activity on catalytic activities and the thermostability of lipases was investigated for transesterification using vinyl acetate and benzyl alcohol as substrates in ionic liquid, [Cnmim][PF6] (n=4,6,8), and benzene. The catalytic activities were enhanced by imprinting in benzene and [C4mim][PF6], and the relations between the transesterification activities and the water activity in both solvents were approximately bell shaped. The reactivity of the transesterification in benzene was higher than that in [C4<br /> mim][PF6]. The effects of water activity and imprinting on the kinetic parameters in [C4mim][PF6] were examined. Without controlling the water content, the values of Km,VA and Km,BA (Michaelis constants of vinyl acetate and benzyl alcohol, respectively) decreased, and the values of Vm (maximum rate) increased by imprinting. On the other hand, by controlling the water content in the organic media, the values of Vm, Km,VA, and Km,BA increased by imprinting. The activities of lipase in ionic liquid are more strongly affected by water activity and imprinting than those in benzene. We observed effects of water activity on thermostability but none from imprinting.

scholarly journals On the Nature of Bacterial Lag

1914 ◽  
Vol 14 (2) ◽  
pp. 215-241 ◽  
Author(s):  
William Jas. Penfold
Keyword(s):  
Maximum Rate ◽  
The Other ◽  
Water Culture ◽  
Rate Of Growth ◽  
Heat Stable ◽  
Other Hand ◽  
Parent Culture ◽  
Peptone Water ◽  
Effect On Growth

(1) If B. coli be subcultured into another sample of the same medium when growing at full pace, it will continue to grow at the same pace.(2) If the maximum rate of growth be interrupted by a short application of cold, growth will recommence without lag on the temperature being raised. If the cold be long continued, lag will tend to reappear.(3) Differences in the size of inoculum have practically no effect on lag in the case of large inoculums, in the case of small ones, on the other hand, diminution of the seeding has the effect of lengthening lag, and this lengthening effect is more marked the smaller the seedings become.(4) Lowering the temperature lengthens the lag. The effect is very similar to the effect on growth.(5) The older a parent culture (within limits) the longer the lag.(6) The length of lag varies with the medium even if adaptation has been arranged for beforehand.(7) Heat-stable products in B. coli cultures on peptone water have, in the case of overnight cultures, but little effect on lag.(8) After washing the bacteria for two hours with saline in order to remove possible inhibiting agents, it was found that the lag, on subculture, still occurred and was indeed slightly longer.(9) If a peptone water culture of B. coli be centrifuged, it is found that the few bacteria remaining in the supernatant commence to grow again at a quick rate but not without a period of lag.

Proteolytic and Lipolytic Activities of some Toxigenic and Nontoxigenic Aspergilli and Penicillia

1980 ◽  
Vol 43 (5) ◽  
pp. 354-355 ◽  
Author(s):  
S. M. EL-GENDY ◽  
E. H. MARTH
Keyword(s):  
Proteolytic Activity ◽  
Aspergillus Flavus ◽  
Aspergillus Parasiticus ◽  
Lipolytic Activity ◽  
The Other ◽  
Aspergillus Ochraceus ◽  
Penicillium Roqueforti ◽  
Two Cultures ◽  
Penicillium Cyclopium ◽  
Penicillium Patulum

Eighteen strains of Aspergillus flavus or Aspergillus parasiticus, one of Aspergillus ochraceus and 12 strains or species of Penicillium, many of them isolated from cheese, were evaluated for their proteolytic and lipolytic activities. Strains of A. flavus exhibited considerable proteolytic and little lipolytic activity, whereas the reverse was true for strains of A. parasiticus. Of the Penicillium cultures tested, 10 exhibited considerable lipolytic activity, but only five had marked proteolytic activity. Two cultures, Penicillium patulum M59, and Penicillium cyclopium No. 8, were markedly lipolytic and proteolytic. Of the other cultures, greatest lipolytic activity was associated with Penicillium roqueforti 849, Penicillium puberulum No. 33, A. parasiticus NRRL 3145 and NRRL 465 and A. ochraceus NRRL 3174, whereas greatest proteolytic activity of all the cultures was associated with P. patulum M59, P. cyclopium No. 25 and A. flavus WB500, 4018, 4098 and NRRL 5565.

The Interaction of Procaine with the Nonmyelinated Nerve Axon

1972 ◽  
Vol 50 (2) ◽  
pp. 174-176 ◽  
Author(s):  
Henry Simpkins ◽  
Elaine Panko ◽  
Sin Tay
Keyword(s):  
Conformational Change ◽  
Potent Inhibitor ◽  
Homarus Americanus ◽  
The Other ◽  
Nerve Axon ◽  
Lipid Structure

The interaction of procaine with the nonmyelinated nerve axon from the legs of Homarus americanus was found to produce a conformational change in the lipid structure of the membrane. This conformational change was also observed after treatment of the nerve with acetylcholine bromide but not with any of the following local anesthetics:lidocaine, carbocaine, prilocaine, and nupercaine. It was also found that procaine is a potent inhibitor of acetylcholinesterase whereas the other anesthetics at the same concentration had little effect.

scholarly journals The unactivated form of the first component of human complement, C1

1976 ◽  
Vol 157 (3) ◽  
pp. 541-548 ◽  
Author(s):  
I Gigli ◽  
R R Porter ◽  
R B Sim
Keyword(s):  
Human Serum ◽  
Proteolytic Activity ◽  
Molar Ratio ◽  
Human Complement ◽  
Peptide Bonds ◽  
Optimum Activity ◽  
Haemolytic Assay ◽  
Subsequent Loss

The first component of complement, C1, was isolated unactivated from human serum by repeated additions of di-isopropyl phosphorofluoridate during isolation. The unactivated subcomponents were also isolated, and evidence is given that the three subcomponents C1q, C1r and C1s account wholly for the activity of component C1 in serum. No evidence could be found for a fourth subcomponent, C1t. The approximate molar proportions of the subcomponents in serum are C1q/C1r/C1s = 1:2:2. Optimum activity by haemolytic assay was found at approximate molar proportions C1q/C1r/C1s of 1:4:4. No activity was found when subcomponents were assayed singly or in pairs, except for subcomponents C1q and C1s, which in molar ratio 1:4 gave 15-20% of the activity of the mixture C1q + C1r + C1s. The proteolytic activity of the isolated subcomponent C1s varied according to the method of activation used. Subcomponents C1q + C1r + C1s and C1q + C1s in the presence of antibody-antigen aggregates were activated and inactivated simultaneously, showing a peak of activity and subsequent loss of activity. Both reactions are probably due to proteolysis, and analysis of the peptide bonds split will be necessary to distinguish these two phenomena.

scholarly journals Proteolytic activity in the stem cambial region of Pinus sylvestris L. - A contribution to the specific differentiation of secondary xylem and phloem

2014 ◽  
Vol 63 (3-4) ◽  
pp. 247-253 ◽  
Author(s):  
Krzysztof J. Rakowski ◽  
Tomasz J. Wodzicki
Keyword(s):  
Pinus Sylvestris ◽  
Protease Inhibitor ◽  
Electrophoretic Mobility ◽  
Proteolytic Activity ◽  
Secondary Xylem ◽  
Cambial Activity ◽  
The Other ◽  
Xylem Differentiation ◽  
Phloem Tissue ◽  
Ph Optimum

Proteolytic activity was studied in the differentiating xylem and phloem of Scots pine (<i>Pinus sylvestris</i> L.) to determine the specificity of xylem and phloem differentiation. The activity of autolytic proteases was demonstrated in the differentiating xylem during spring, summer and autumn and it was not detectable during winter. It was initiated with the onset of cambial activity in spring and unchanged during subsequent stages of xylem differentiation. The same proteolytic activity was not detectable in the extract of fresh phloem tissue. It could be detected in phloem after removal of the inhibitor found in the extract. The same pH optimum was determined for proteases extracted from xylem and phloem. However, their identity remains uncertain because of different electrophoretic mobility. On the other hand the presence of protease inhibitor in phloem tissue can be an important factor im determining the specificity of xylem an phloem differentiation.

Fibrinolytic Properties of Proteases Derived from Human, Dog and Rabbit Leukocytes

1963 ◽  
Vol 10 (02) ◽  
pp. 379-389 ◽  
Author(s):  
Henry Gans
Keyword(s):  
Plasminogen Activator ◽  
Proteolytic Activity ◽  
Human Cell ◽  
Fold Increase ◽  
The Other ◽  
Human Leukocytes ◽  
Plasminogen Activator Activity ◽  
Other Hand

SummaryIntact and disintegrated human, dog and rabbit leukocytes were studied for their ability to lyse fibrin. It was noted that broken-up rabbit leukocytes fail to lyse bovine or rabbit fibrin. Human and dog leukocytes, on the other hand, readily lyse bovine fibrin.Prior incubation at pH 1 and pH 8 resulted in maximally active human cell preparations. Similar results were obtained with dog cells upon prior incubation at pH 4 and pH 8. Loss of activity was noted upon prior incubation for 15 minutes at 56° C. Adsorption of human leukocytes with celite and charcoal resulted in a 2 and 21/2 fold increase in activity.The noted lysis was found to result from proteolytic activity as well as from plasminogen activator activity. The results to these studies suggest that autolysis of relatively few leukocytes will produce a rapid breakdown of considerable amounts of fibrin.

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