scholarly journals Structural similarity of chymopapain forms as indicated by circular dichroism

1989 ◽  
Vol 257 (1) ◽  
pp. 183-186 ◽  
Author(s):  
S Solis-Mendiola ◽  
R Zubillaga-Luna ◽  
A Rojo-Dominguez ◽  
A Hernandez-Arana
Keyword(s):  
Liquid Chromatography ◽  
High Resolution ◽  
Cation Exchange ◽  
Proteolytic Activity ◽  
Structural Similarity ◽  
Tertiary Structures ◽  
Exchange Column ◽  
Cation Exchange Column ◽  
Modified Proteins ◽  
Circular Dichroïsm

Four chymopapain forms were isolated by high-resolution liquid chromatography on a cation-exchange column. The three major forms possess nearly identical secondary and tertiary structures, as judged from their c.d. spectra; these components showed similar proteolytic activity and Mr values close to that of papain. The fourth isolated component seems to be a mixture of modified proteins.

Determination of haemoglobin A1c by liquid chromatography using a new cation-exchange column

2003 ◽  
Vol 791 (1-2) ◽  
pp. 73-83 ◽  
Author(s):  
Maria Beatriz de la Calle Guntiñas ◽  
René Wissiack ◽  
Guy Bordin ◽  
Adela Rosa Rodrı́guez
Keyword(s):  
Liquid Chromatography ◽  
Cation Exchange ◽  
Haemoglobin A1c ◽  
Exchange Column ◽  
Cation Exchange Column

scholarly journals Measurement of Bromate in Bread by Liquid Chromatography with Post-Column Flow Reactor Detection

2000 ◽  
Vol 83 (2) ◽  
pp. 347-355 ◽  
Author(s):  
Katsuichi Himata ◽  
Masaaki Noda ◽  
Susumu Ando ◽  
Yuji Yamada
Keyword(s):  
Liquid Chromatography ◽  
Cation Exchange ◽  
Flow Reactor ◽  
Solid Phase ◽  
Silver Ions ◽  
Reversed Phase ◽  
Phase Detection ◽  
Exchange Column ◽  
Baked Goods ◽  
Cation Exchange Column

Abstract This method is suitable for the determination of bromate residues in a variety of baked goods. The peer-verified method trial was performed on white bread, multigrain bread, and coffee cake spiked with known levels of potassium bromate. The analytical portion is extracted with deionized water to remove bromate from the bulk of the baked product. The aqueous extract is carried through a series of steps to remove co-extractives that would interfere with the liquid chromatography (LC) in the determinative step or hasten the deterioration of the LC column. The extract is filtered before passing it through a reversed-phase solid-phase extraction (SPE) column and a cation-exchange column in the silver form to remove lipids and chloride, respectively. Ultrafiltration is then used to remove proteins with molecular weights of >30 000 daltons. Finally, a cation-exchange column in the sodium form is used to remove silver ions from the extract. The determinative step uses LC with a reversed-phase column and an ion-pairing agent in the mobile phase. Detection is based on the post-column reaction of bromate with o-dianisidine to form an oxidation product that is quantitated spectrophotometrically at 450 nm. Overall agreement between the submitting and peer laboratories was quite good. For bromate levels of 10–52 ppb, overall mean recoveries were 76.9 and 78.8% for the submitting and peer laboratories, respectively. The standard deviations were higher for the results of the peer laboratory, probably because of the generally higher level of baseline noise present in the chromatograms. The results demonstrate that the method provides adequate accuracy with low-fat as well as high-fat foods. Bromate at levels as low as 5 ppb (ng/g) can be detected with the method.

scholarly journals Channel-Forming (Porin) Activity in Herpetosiphon aurantiacus Hp a2

2004 ◽  
Vol 186 (19) ◽  
pp. 6667-6670 ◽  
Author(s):  
Rainer Harwardt ◽  
Elke Maier ◽  
Hans Reichenbach ◽  
Jürgen Weckesser ◽  
Roland Benz
Keyword(s):  
Liquid Chromatography ◽  
Cation Exchange ◽  
Lipid Bilayers ◽  
Fast Protein Liquid Chromatography ◽  
Permeability Barrier ◽  
Exchange Column ◽  
Cation Exchange Column ◽  
Cell Envelopes ◽  
Gliding Bacterium

ABSTRACT Detergent extracts of cell envelopes of the gliding bacterium Herpetosiphon aurantiacus formed channels in lipid bilayers. Fast protein liquid chromatography across a HiTrap-Q cation-exchange column demonstrated that a 45-kDa protein forms the channel. The observation of a channel-forming protein suggests that Herpetosiphon aurantiacus Hp a2 has a permeability barrier on its surface.

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