Amino Acid Side Groups Research Articles

Chromatography of polypeptides and proteins on hydroxyapatite columns: Some new developments

The chromatographic behavior of polypeptides and proteins and the adsorption of amino acids on hydroxyapatite have been investigated in order to reach a better understanding of the adsorption-elution process and to obtain further information on the amino acid side-groups involved in the protein-hydroxyapatite interaction. The main findings of the present work are the following: (1) basic proteins can be eluted from hydroxyapatite columns, not only by the usual phosphate buffer (pH 6.8), but also by NaCl or KCl solutions. In contrast, the interaction of neutral and acidic proteins with hydroxyapatite by very low (0.001–0.02 M) concentrations of CaCl 2, whereas this solvent does not affect the adsorption of neutral and acidic proteins even at very high (3 M) concentrations. The above results, as well as other findings concerning the chromatographic behavior of synthetic polypeptides and the adsorption properties of amino acids, very strongly support the idea that crystals have two different adsorption sites on their surface, to be identified with phosphate and calcium, and that these are responsible for the binding of basic and acidic side groups of proteins, respectively.

Effect of the?-amino acid radical on the cleavage rate of the carbocyclohexyloxy group during hydro brominolysis

A series of carbocyclohexyloxyamino acids were subjected to hydrobrominolysis. The side groups of the amino acids affect the cleavage rate of the CCO group during hydrobrominolysis, which is probably determined by the total influence of the induction and steric effects of these groups.

軟体動物石灰化組織の鉱物化に関する研究-IV

1) The selective fixation of 45Ca in deposits formed on coverslip preparations obtained in several marine molluscs was investigated with radioautographic stripping film, and the mineralization of the organic matrix, especially the nucleation of mineral phase, was discussed on the basis of the obtained results. 2) The labeled calcium may be selectively localized in the acid mucopolysaccharides in the organic matrix, and deposit concentrically in the metachromatic organic crystals from which a remarkable large polycrystalline appears to be crystallized before long. 3) It was supposed that the metachromatic substances combined with certain amino acid side groups in the conchiolin protein may act as the specific sites for the crystal nucleation under certain conditions. 4) The distribution of 45Ca within mineral crystals may indicate the mode of crystal growth. 5) The metachromatic organic crystals revealed the reticulated structure resembledd to that of the Pinctada shell conchiolin and were essentially similar to the underlying ground matrix on morphological viewpoint. The author expresses his sincere thanks to Prof. Dr. Toshio SUDOU of Tokyo University of Education for his useful advices and encouragement.