Practical staining method: T-OPA triple stain

The following procedure has proven to be successful as routine trichrome stain on paraffin embedded material: 1) Mayer's hemalum for 10 min, followed by running tap water wash; 2) staining in 1% Orange G in 1% acqueous PTA for 5 min and rinsing a few seconds in distilled water; 3) Aniline blue 1% acqueous for 5 min, followed by few seconds distilled water wash. Dehidratation in ethanol, or by blotting followed by t-buthanol or 1:3 terpineol-xylene, clearing and mounting, completed the procedure.     

The activity of PEG-modified chymotrypsin in aqueous and organic media

Summary Polyethylene glycol-modified chymotrypsin was prepared by activation of monomethoxypolyethylene glycols with phenylchloroformates and subsequent coupling with free enzyme. The modification was correlated with enzyme activity in aqueous solution and in organic solvents. The activity in aqueous solution was high (80% of that of non-modified enzyme), even at high degrees of modification. The modified protease was soluble in benzene and DMF and catalyzed transesterification in cyclohexane.     

CHARACTERIZATION OF MULTIPLE FORMS OF BRAIN TUBULIN SUBUNITS

Abstract— Microtubular protein was isolated from rat forebrain by biochemical purification (ammonium sulfate precipitation followed by DEAE cellulose chromatography) or by two cycles of aggregation-disaggregation. The protein subunit structure was examined on two-dimensional electrophoretograms: first dimension, urea isoelectric focusing gel; second dimension, sodium dodecyl sulfate exponential acrylamide slab gel. Two forms of α tubulin were separated in the second dimension on the basis of different rates of migration (α and α₂). Each of these species was further separated into at least three forms with different isoelectric points. β Tubulin was separated into a minor species (BI) and a major species β₂). Multiple subunits were observed using protein from either purification method and in a two-dimensional electrophoretogram of total supernatant proteins from rat brain. Separation and visualization of multiple forms of α and β tubulin is consistent with reports that provide evidence for post-translational modification of these proteins.     

HPLC method to characterize cyanogen bromide collagen fractions containing pyridinoline groups.

The HPLC method here described allows to separate CNBr collagen peptides within 2.5 h by reversed phase and gradient elution. The method is useful to determine both peptide bond and pyridinoline groups by absorbance spectophotometry. The fractions can be recovered and then submitted to other characterization techniques.