Articles written in Journal of Biosciences
Volume 27 Issue 5 September 2002 pp 515-520 Articles
Adaptation to high salinity and low or high temperature is essential for bacteria to survive. Accumulation of exogenous osmolytes is one of the ways that helps bacteria to survive under such extracellular stress. We have analysed the capability of various L-amino acids and their D-isomers to act as osmolytes and thus enable
Volume 33 Issue 2 June 2008 pp 195-207 Articles
Human seminal proteinase and prostate-specific antigen (PSA) were each isolated from human seminal fluid and compared. Both are glycoproteins of 32–34 kDa with protease activities. Based on some physicochemical, enzymatic and immunological properties, it is concluded that these proteins are in fact identical. The protein exhibits properties similar to kallikrein-like serine protease, trypsin, chymotrypsin and thiol acid protease. Tests of the activity of the enzyme against some potential natural and synthetic substrates showed that bovine serum albumin was more readily hydrolysed than casein. The results of this study should be useful in purifying and assaying this protein. Based on published studies and the present results, the broad proteolytic specificity of human seminal proteinase suggests a role for this protein in several physiological functions.
Volume 34 Issue 2 June 2009 pp 321-331 Review
Intracellular organic osmolytes are present in certain organisms adapted to harsh environments. These osmolytes protect intracellular macromolecules against denaturing environmental stress. In contrast to the usually benign effects of most organic osmolytes, the waste product urea is a well-known perturbant of macromolecules. Although urea is a perturbing solute which inhibits enzyme activity and stability, it is employed by some species as a major osmolyte. The answer to this paradox was believed to be the discovery of protective osmolytes (methylamines). We review the current state of knowledge on the various ways of counteracting the harmful effects of urea in nature and the mechanisms for this. This review ends with the mechanistic idea that cellular salt (KCl/NaCl) plays a crucial role in counteracting the effects of urea, either by inducing required chaperones or methylamines, or by thermodynamic interactions with urea-destabilised proteins. We also propose future opportunities and challenges in the field.