Proteolytic enzymes

About: Proteolytic enzymes is a research topic. Over the lifetime, 23096 publications have been published within this topic receiving 835544 citations.

Spatiotemporal expression patterns of metalloproteinases and their inhibitors in the postnatal developing rat cerebellum.

Abstract: Matrix metalloproteinases (MMPs) are proteolytic enzymes that degrade the components of the extracellular matrix (ECM). The balance between MMPs and their inhibitors [tissue inhibitors of metalloproteinases (TIMPs)] in the pericellular environment determines the most significant proteolytic events in tissue remodeling. In vitro evidence is accumulating that these molecules may be crucial in the maturation of neural cells. Here, we investigated the in vivo expression of MMPs 2, 3, and 9 and TIMPs 1, 2, and 3 in the developing and adult rat cerebellum using immunohistochemistry and in situ hybridization. During postnatal development, all Purkinje (PK) cell somata expressed all the MMPs and TIMPs studied, whereas their growing dendritic trees expressed only MMP 3 and TIMP 3. In the adult, MMP 3 was confined to PK cell bodies, whereas TIMP 3 was expressed in PK cell somata and processes. Irrespective of the developmental stage, Bergmann glial processes contained only MMP 9, but their somata contained both TIMP 1 and MMP 9. In granular cells, MMPs 3 and 9 and TIMPs 1, 2, and 3 were chiefly detected at a time when migration is known to be maximal; except for that of TIMP 1, their expression persisted in the internal granular layer in the adult. The functional relevance of MMP expression was verified by gelatin zymography. MMP 9 activity was maximal on postnatal day 10 (P10) and was detectable at a low level on P15 and in the adult, whereas MMP 2 activity remained similar throughout postnatal development. Regional and cell-specific expression of MMPs and TIMPs closely reflects the successive stages of cerebellar development, thereby suggesting a pivotal role for ECM proteolysis in brain development and plasticity.

Covalent modification of the iron protein of nitrogenase from Rhodospirillum rubrum by adenosine diphosphoribosylation of a specific arginine residue

Abstract: Nitrogenase in Rhodospirillum rubrum is inactivated in vivo by the covalent modification of the Fe protein with a nucleotide. The preparation of two modified peptides derived from proteolytic digestion of the inactive Fe protein is described. The modifying group is shown to be adenosine diphosphoribose, linked through the terminal ribose to a guanidino nitrogen of arginine. The structural features were established by using proton and phosphorus NMR, positive- and negative-ion fast atom bombardment mass spectrometry, and fast atom bombardment/collisionally activated decomposition mass spectrometry. Spectral methods along with chromatographic analysis and sequential degradation established the sequence of the modification site of Fe protein as Gly-Arg(ADR-ribose)-Gly-Val-Ile-Thr. This corresponds to the sequence in the Fe protein from Azotobacter vinelandii for amino acid residues 99 to 104.