Two New Proton NMR Standards for High Tem p e r a t u r e s and Aqueous Solutions · Carrier-Bound Enzymes · Non-Bleeding p H Indicators
EM ANALYTICAL REPORT Two N e w P r o t o n N M R S t a n d a r d s for H i g h Tem p e r a t u r e s a n d A q u e o u s Solutions T h e t e m p e r a t u r e r a n g e a b o v e 100 °C is i m p o r t a n t for studies of r o t a t i o n b a r r i e r s in m o l e c u l e s w i t h hin d e r e d rotation, of t r a n s i t i o n e n t h a l p i e s of s t r u c t u r a l isomers a n d of NMR emission p h e n o m e n a after chem ically i n d u c e d dynamic n u c l e a r polarization. Tetramethylsilane (TMS) is u s e d in this t e m p e r a t u r e r a n g e with difficulty b e c a u s e of its low boiling point. Cyclosilane w i t h its boiling point of 208 °C would b e ideal h a d it not two NMR signals, from m e t h y l p r o t o n s n e a r 0 a n d from m e t h y l e n e p r o t o n s at —0.327 p p m . So, w e r e m o v e d t h e CH 3 signals by r e p l a c i n g t h e m w i t h trid e u t e r o m e t h y l groups. T h e result is cyclosilane-djg. Its solubility in solvents u s e d for h i g h t e m p e r a t u r e NMR m e a s u r e m e n t s is sufficient t o obtain a s t a b l e locking signal u p t o t h e boiling point of t h e solvent used. It h a s o n e s h a r p r e s o n a n c e signal w i t h a half w i d t h of 0.5 Hz at — 0.327 p p m a n d allows r e c o r d i n g of u n d i s t u r b e d s p e c t r a downfield of TMS. D,C
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T h e big d i s a d v a n t a g e of p H p a p e r s h a s b e e n t h e bleeding of t h e d y e c o m p o n e n t s especially in a l k a l i n e a n d non-buffered solutions. Bleeding of d y e compo n e n t s from mixed indicators gives color g r a d i e n t s , m a k i n g color comparison u n r e l i a b l e . EM offers indicator sticks with t h e d y e b o u n d covalently t o t h e carrier. Color c h a n g e is i n d i c a t e d b u t it cannot b e w a s h e d out. °2Νχ HO
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Λ—S0 2 — CHj
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As shown in t h e above formula, t h e indicator dyes a r e a t t a c h e d t o cellulose molecules via a sulfonylethyl e t h e r group. F r o m t h e d y e d cellulose, p a p e r is m a d e which is a t t a c h e d t o a plastic s t r i p s u p p o r t . T h e s e p H r a n g e s a r e available 0-14, 0-6, 5-10, 7.5-14, 0-2.5, 2.5-4.5, 4.0-7.0, 6.5-10.0,11.0-13.0.
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Non-Bleeding p H Indicators
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l b o b t a i n a good NMR s t a n d a r d for a q u e o u s solu tions, w e s t a r t e d w i t h 3-trimethylsilylpropionic acid a n d r e p l a c e d t h e t w o m e t h y l e n e groups w i t h d e u t e r o m e t h y l e n e groups. T h i s r e m o v e d d i s t u r b i n g p r o t o n signals. T h e n e w s t a n d a r d is w a t e r soluble a n d h a s a s t r o n g r e s o n a n c e signal, like TMS, at 0.00 p p m .
E M Laboratories, Inc. aftuiate ot Ε . M e r ç k , D a r m s t a d t , U e r m a n y 500 E x e c u t i v e B o u l e v a r d , Elmsford, New York 10523 P h o n e 914/592-4660
C a r r i e r Bound, Highly Active, Insoluble E n z y m e s Our r e s e a r c h l a b o r a t o r i e s h a v e d e v e l o p e d a n e w m e t h o d t o b i n d e n z y m e s covalently t o n a t u r a l a n d synthetic carriers. Advantages a r e : They can be re c o v e r e d a n d t h e y do n o t c o n t a m i n a t e s a m p l e . T h e y can b e u s e d b a t c h w i s e or i n a continuous chromatography-like process. T h e y a r e s t a b l e a n d highly active. Most a r e p r o t e a s e s for t h e controlled d e g r a d a t i o n of p r o t e i n s , b u t o t h e r usages c a n b e p r o j e c t e d . A c t i v i t y of B o v i n e T r y p s i n B o u n d t o C M - c o l l u l o s e Insoluble derivative B A E E ( p H 9.5; 30 "C) 10 U / m g ΒΑΡΑ ( p H 8.0; 85 °C) 0.1 U / m g Protein content 35% Specific activity of b o u n d p r o t e i n BAEE 35 U / m g p r o t e i n ΒΑΡΑ 0.3 U / m g p r o t e i n
E M L a b o r a t o r i e s Inc. 500 E x e c u t i v e B o u l e v a r d Elmsf ord, New York 10523 P l e a s e s e n d m e information a b o u t : NMR S t a n d a r d s Samples of non-bleeding p H indicator sticks Carrier-bound enzymes
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Free enzyme 80 U / m g 2.0 U / m g 100%
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60 U / m g 2.0 U / m g
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O t h e r available e n z y m e s a r e insoluble b r o m e l i n , α -chymotrypsin, ficin, p a p a i n , p r o n a s e , p r o t e i n a s e k, r i b o n u c l e a s e , subtilisin, t r y p s i n (porcine), a n d t r y p s i n inhibitor.
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