Physical and chemical studies of a low-molecular-weight form of urease

Abstract

1. A new form of enzymically active jack-bean [Canavalia ensiformis (L.) DC] urease corresponding to an S(20,w) value of 11.8s and a molecular weight of 260000 was investigated. 2. Conversion of 18s urease (EC 3.5.1.5) into the 12s form depends on both low protein concentration and pH. Above pH5.3 urease exists in the 18s form and below pH4.8 in the 12s form; between these two pH values a 12s-18s rapid-equilibrium process is observed. 3. Comparison of the properties of 18s and 12s urease indicated no major differences. 4. A survey of other good urease sources revealed that the 12s form can also be obtained from soya bean (Glycine soja Sieb. and Zucc. cultivar Biloxi) and the bacterium Bacillus pasteurii (Miguel) Migula, but not from watermelon (Citrullus vulgaris Schrad. cultivar Congo). 5. The 12s forms from jack bean and Bacillus pasteurii did not hybridize.

The subunit structure of jack-bean urease

“…ysteine, lysine and Reithel et al (1964), Sehgal & Naylor (1966 and ,ttem of the digest we in the present work have isolated urease of iumber of resolved specific activity in the range 160-180 Sumner but three of these units/mg. at 22-25°; the purity of the preparations No 'core' material has been demonstrated by ultracentrifugation (Reithel et al 1964), polyacrylamide-gel electroylamide-gel electrophoresis (Blattler et al 1967;Tanis & Naylor, 1968), Estigation are sum-and confirmed by the latter technique and Nlard proteins had terminal studies in the present work. The specific ) their molecular activity of these preparations is but little changed rtionship between from the 129 Sumner units/mg.…”

“…The smallest active unit yet found has a molecular weight of about 240 000 (Blattler et al 1967;Tanis & Naylor, 1968), and the data of Kobashi et al (1966) suggest that this unit has only one active site. It might therefore be anticipated that further dissociation would result in inactivation, and this does in fact happen when the structural subunit is produced by dissolving polymeric urease in 6M-guanidine hydrochloride (Tanis & Naylor, 1968) or in sodium dodecyl sulphate (Gorin, Mamiya & Chin, 1967). However, both of these reagents inactivate many enzymes (Reithel, 1963), and in this case it is not possible to separate the effect of denaturation from that of dissociation.…”

“…A number of the components found originally in urease preparations are now known to be active; the large 28s, 36s and 46s molecules (Kuff, Hogeboom & Striebich, 1955) are active and dissociate to the 19s species in the presence of reducing agents (Creeth & Nichol, 1960;Reithel & Robbins, 1967). More recently it has been shown that the 19s unit itself can be reversibly halved to give an active 10-12s species of molecular weight 190000 (Gorin, Chin & Wang, 1968), 236000 (Blattler, Contaxis & Reithel, 1967) or 262000 (Tanis & Naylor, 1968).…”

Dynamic co-expression modular network analysis in nonalcoholic fatty liver disease

“…Pathway enrichment showed that response to copper ion and cellular response to copper ion were enriched in M3. Copper has been proven to play a major role in NAFLD [ 38 ], and copper homeostasis could counteract the progression of NAFLD [ 39 ]. In the hub genes of M3, SNCA and APOE were reported to be associated with copper ion related pathways.…”

Final Technical Report for DOE Award DE-FG02-07ER64403 [Modeling of Microbially Induced Calcite Precipitation for the Immobilization of Strontium-90 Using a Variable Velocity Streamtube Ensemble]

“…must be entered in mol/kgw. To convert the given units of g/l to mol/kgw, the molecular weight of urease is approximated at 480,000 g/mol (Tanis et al 1968). Additionally, for dilute solutions as this, 1 liter of water is approximately 1 kg of water.…”