Title : Transglutaminase from rat coagulating gland secretion
Abstract :
- Post-translational modifications and activation by phosphatidic acids
- Structural and biochemical characteristics of transglutaminase purified by a rapid chromatographic procedure from the rat coagulating gland (anterior prostate) secretion are reported
- Fast atom bombardment mapping and automated Edman degradation experiments allowed us to verify that at least 85% of the entire transglutaminase amino acid sequence is identical to that derived from the cDNA of the major androgen-dependent rat prostate protein called DP1
- The enzyme was found NH2 terminally blocked and largely post-translationally modified, since the presence of N-linked oligosaccharides , as well as of complex lipidic structures , was observed
- Mass spectral analysis showed that Asn-408 and -488 are the glycosylated sites , the N-linked structures identified belonging to both high-mannose and complex type glycans.
- The presence of myo-inositol, of glycerol bound fatty acids, and the high content of mannose residues, are in agreement with previous observations suggesting that a lipid anchor is bound to coagulating gland secretion transglutaminase
- Furthermore, two tightly bound calcium ions per molecule of enzyme were detected
- Finally, a strong stimulation of the enzyme activity in vitro by both SDS and a variety of phosphatidic acids was observed
- The reported structural and functional peculiarities should definitively lead to consider the prostate enzyme as a new member (type IV) of the transglutaminase family