Clostridium thermocellum endoglucanase D (EC 3.2.1.4: EGD), which is encoded by the celD gene, was found to bind Ca2+ with an association constant of 2.03 x 10(6) M-1. Ca2+ stimulated the activity of EGD towards swollen Avicel by 2-fold. In the presence of Ca2+, the Kd of the enzyme towards p-nitrophenyl-beta-D-cellobioside and carboxymethylcellulose was decreased by 4-fold. Furthermore, Ca2+ increased the half-life of the enzyme at 75 degrees C from 13 to 47 min. Since the 3' sequence of celD encodes a duplicated region sharing similarities with the Ca2+-binding site of several Ca2+-binding proteins, a deleted clone was constructed and used to purify a truncated form of the enzyme which no longer contained the duplicated region. The truncated enzyme was very similar to EGD expressed from the intact gene with respect to activity, Ca2(+)-binding kinetics and Ca2+ effects on substrate binding and thermostability. Thus the latter parameters do not appear to be mediated through the duplicated conserved region.
Desuljoribrio uulgcrris (Hildenborough) was grown on lactate with either a N,/C02 or a H 2 / C 0 2 gas phase. H, increased the growth yield on lactate and had a sparing effect on lactate utilization, without altering the growth rate or hydrogenase level. Growth on acetate plus CO, with H, as sole energy source did not require an extensive adaptation period. Addition of lactate to cultures growing on acetate and H,/C02 resulted in a switch from acetate to lactate utilization. In lactate-limited medium under H2/C02 biphasic growth was observed. Lactate was oxidized first with production of acetate, followed by a second phase of growth on the acetate. Under this condition H2 did not provide any supplementary energy during growth on lactate, as was evident from the ratio of lactate utilized to acetate produced.
SUMMARY Plasma fibrinolytic activity and plasma inhibitory activity against urokinase and tissue activator were measured in primigravidae with moderate or severe pre-eclampsia and in gestationmatched primigravidae with uncomplicated pregnancy. The mean levels of fibrinolytic activity and inhibitory activity against urokinase and tissue activator did not differ significantly between the pre-eclampsia and uncomplicated pregnancy groups. The pattern of inhibitory fractions of plasminogen-depleted plasma from pre-eclamptic and uncomplicated primigravidae after gel filtration on Sephadex G-100 was similar.
SummaryThe activity of urokinase and tissue activator on fibrin plates was inhibited by plasma from women in the third trimester of pregnancy to a greater extent than by non-pregnant plasma. Pregnancy also inhibited the amidolytic activity of urokinase. The high molecular weight fractions of pregnancy plasma gel filtered on Sephadex G-200 showed comparable inhibitory activity against urokinase as fractions for non-pregnant plasma; in contrast with non-pregnant plasma, the lower molecular weight fractions of pregnancy plasma were markedly inhibitory against urokinase. Plasma exposed to lysine-Sepharose to remove plasminogen and then fractionated on Sephadex G-100 provided a pattern of three areas of inhibition against tissue activator similar to that seen in non-pregnant plasma. The urokinase-inhibitory activity of lower molecular weight fractions of plasma separated on Sephadex G-200 fell within 1 hr of delivery and fell further over the following 18 to 30 hr.
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