RESUMEN
Monoliths are attractive stationary phases for purification of large biomolecules like proteins because of their flow-unaffected properties. Isolation of histidine containing proteins to high purity can be efficiently performed using metal-chelate interactions within a single chromatographic step. In this work, we investigated properties of commercial metal-chelate methacrylate monoliths-Convective Interaction Media (CIM). Analytical CIM disk monolithic columns and CIM 8 ml monolithic columns were used for purification of tumor necrosis factor-alpha (TNF-alpha) analog LK-801 and green fluorescence protein with 6 histidine tag (GFP-6His). In both cases, purity over 90% was achieved. Dynamic binding capacity at 10% of breakthrough was around 17-18 mg/ml for LK-801 and around 30 mg/ml for GFP-6His. Adsorption isotherm revealed that the maximal capacity is achieved at protein concentration above 60 microg/ml. Dynamic binding capacity and resolution were found to be flow unaffected.
Asunto(s)
Quelantes/química , Metales/química , Metacrilatos/química , Adsorción , Cromatografía Líquida de Alta Presión/instrumentación , Cromatografía Líquida de Alta Presión/métodos , Cobre/química , Electroforesis en Gel de Poliacrilamida , Proteínas Fluorescentes Verdes/aislamiento & purificación , Factor de Necrosis Tumoral alfa/aislamiento & purificaciónRESUMEN
Proton nuclear magnetic resonance spectroscopy was used to evaluate changes in plasma lipoproteins in patients with squamous cell head and neck cancer. Plasma from 14 patients was analyzed by proton nuclear magnetic resonance spectroscopy, and line widths and fast and slow methyl and methylene transverse relaxation values were obtained. In addition, the lipid and lipoprotein concentrations in the sera of these patients were measured by standard biochemical techniques. Preliminary results suggested that squamous cell carcinomas of the head and neck with nodal metastases are associated with measureable changes in slow methylene transverse relaxation values, as compared with controls. These findings indicate the presence of a new lipoprotein complex in patients with squamous cell carcinomas of the head and neck with nodal metastases.