Studies on the agglutinating activity of pancreatic extracts and its relevance to function

Summary Agglutination of washed rabbit erythrocytes caused by pancreatic acinar cell extract was inhibited by glucose, maltose and cellobiose. Process of elimination and purification divulged that the acinar cell enzyme -amylase was responsible for attributing the agglutinin activity. Assay of enzyme and agglutinin activity data of different fractions of re-purified -amylase eluted from HPLC column showed that both the activity resides in the same fraction which suggests that the enzyme binds to the glucosyl residues of the rabbit erythrocytes via the carbohydrate binding/catalytic sites. Similar properties of other glycosidases were also noted.     

Purification and characterization of metallothionein from liver of cadmium exposed Rhesus monkeys (Macaca mulatta)

Metallothionein (MT) a low molecular weight, Cd-binding, cysteine rich, cytosolic protein has been isolated, purified and characterized from cadmium exposed Rhesus monkeys maintained on protein calorie malnourished (PCM) diet. Metallothionein was resolved into three isoforms i.e. MT_a, MT_b and MTV_c. The ratio of Cd, Zn and Cu varied in these isometallothioneins. MT_c was the major isometallothionein. UV Spectra of MT_c revealed the presence of mercaptide bonds and absence of aromatic amino acids. These observations were further confirmed by amino acid analysis of MT_c which demonstrated high cysteine content (22.6) followed by serine, glycine and lysine. The molecular weight of MT_c as determined by gel filtration and amino acid analysis was 13000 and 6398 daltons respectively. This demonstrates that MT_c is a non-globular ellipsoid polypeptide. MT_c showed a unique property of binding selenium. Monkey liver metallothionein was immunologically identical with human metallothionein. All the characteristics of MT_c obtained in the present study reveal a similarity between monkey and human metallothionein probably due to closer phylogenetic relationship between the two species.     

Modulation of sialic acid-binding proteins of rat uterus in response to changing hormonal milieu

A group of sialic acid binding (SAS) agglutinins has been isolated from the rat uteri at different stages [Proestrus (P), estrus (E) and diestrus (D)] of estrous cycle. Studies of biochemical properties indicate that SAS agglutinins are glycoprotein in nature having molecular weights between 28–31 Kd and microheterogenous pI. Function-based characterization revealed that inspite of the fact that all three proteins exhibit sialic acid binding property, the sialic acid binding affinities, calculated from Scatchard analysis, using 4-methylumbelliferyl sialic acid as a ligand, varied in stage specific manner (Ka:D-SAS-9.03×10⁵ M^–1, P-SAS-2.33×10⁵ M^–1, E-SAS-2.13×10⁵ M^–1). Circular dichroism spectra of these three agglutinins suggested that differences exist in the secondary structures of the proteins isolated from different stages. Removal of carbohydrate moiety by trifluoromethane sulfonic acid treatment and CNBr cleavage studies showed some homology between these proteins, however, the variation in the carbohydrate moiety was apparent from the sugar analysis data. Functionally and immunologically these proteins can be grouped as estrogenic and progestogenic SAS agglutinins.     

Design of a New Peptide Substrate Probe of the Putative Biomarker Legumain with Potential Application in Prostate Cancer Diagnosis Ex Vivo

International Journal of Peptide Research and Therapeutics - The lysosomal endoprotease legumain (asparaginyl endoprotease) has been proposed as a putative biomarker in prostate tumours, in which...     

QSAR studies in substituted 1,2,3,4,6,7,12,12a-octa-hydropyrazino[2',1':6,1]pyrido[3,4-b]indoles--a potent class of neuroleptics

A series of nineteen substituted 1,2,3,4,6,7,12,12a-octahydropyrazino[2',1':6,1]pyrido[3, 4-b]indoles analogues of neuroleptic drug, Centbutindole have been studied using quantitative structure-activity relationship analysis. The derived models display good fits to the experimental data (r>or=0.75) having good predictive power (r(cv)>or=0.688). The best model describes a high correlation between predicted and experimental activity data (r=0.967). Statistical analysis of the equation populations indicates that hydrophobicity (as measured by pi(R), logP(o/w) and SlogP_VSA8), dipole y and structural parameters in terms of indicator variable, (In(1)) and globularity are important variables in describing the variation in the neuroleptic activity in the series.     

Myostatin-deficient mice lose more skeletal muscle mass than wild-type controls during hindlimb suspension

Myostatin inhibits myogenesis. Therefore, we sought to determine if mice lacking the myostatin gene [Mstn(-/-)] would lose less muscle mass than wild-type mice during 7 days of hindlimb suspension (HS). Male Mstn(-/-) and wild-type (C57) mice were subjected to HS or served as ground-based controls (n = 6/group). Wild-type mice lost 8% of body mass and approximately 13% of wet mass from biceps femoris, quadriceps femoris, and soleus, whereas the mass of extensor digitorum longus (EDL) was unchanged after HS. Unexpectedly, Mstn(-/-) mice lost more body (13%, P < 0.05) and quadriceps femoris (17%, P < 0.05) mass than wild-type mice and lost 33% of EDL mass (P < 0.01) after HS. Protein expression of myostatin in biceps femoris and quadriceps femoris was not altered, whereas expression of MyoD, Myf-5, and myogenin increased in wild-type mice and tended to decrease in muscles of Mstn(-/-) mice. These data suggest that HS induced myogenesis in wild-type mice to counter atrophy, whereas myogenesis was not induced in Mstn(-/-) mice, thereby resulting in a greater loss of muscle mass.