Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.27 (thermolysin)
 1,894 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chlamydomonas flagellar sexual agglutinins are responsible for the adhesion of opposite mating-type (plus and minus) gametes during the first stages of mating. Purification and partial characterization of the plus agglutinin was previously reported (Adair, W. S., C. J. Hwang, and U. W. Goodenough, 1983, Cell, 33:183-193). Here we characterize the purified minus molecule. We show it to be a high molecular weight, hydroxyproline-rich glycoprotein that migrates in the 3% stacking region of an SDS-polyacrylamide gel and is absent from two nonagglutinating minus mutants. Plus and minus agglutinins are remarkably similar, although nonidentical, in amino acid composition, molecular morphology, and reactivity in vivo and in vitro with monoclonal antibodies raised against the plus agglutinin. Moreover, the adhesiveness of both plus and minus agglutinins, when coupled to agarose beads, is abolished by thermolysin, trypsin, periodate, alkaline borohydride, reducing agents, or heat, but unaffected by exo- or endoglycosidases. The minus agglutinin, however, migrates just ahead of the plus molecule on SDS PAGE, is excluded from an anion-exchange (Mono Q) column, elutes earlier during hydrophobic interaction (Bio-gel TSK Phenyl 5PW) chromatography, and is sensitive to chymotrypsin digestion (unlike the plus agglutinin); therefore, it differs from the plus agglutinin in apparent molecular weight, net charge, relative hydrophobicity and proteolytic susceptibility. Nevertheless, our results generally demonstrate a high degree of homology between these complementary cell-cell recognition/adhesion molecules, which suggests that they are specified by genes that have a common evolutionary origin.
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PMID:Characterization of the purified Chlamydomonas minus agglutinin. 241 36

We previously showed that serum-derived 85-kDa proteins (SHAPs, serum-derived hyaluronan associated proteins) are firmly bound to hyaluronan (HA) synthesized by cultured fibroblasts. SHAPs were then identified to be the heavy chains of inter-alpha-trypsin inhibitor (ITI) (Huang, L., Yoneda, M., and Kimata, K. (1993) J. Biol. Chem. 268, 26725-26730). In this study, the SHAP.HA complex was isolated from pathological synovial fluid from human arthritis patients. The SHAP.HA complex was digested with thermolysin, followed by CsCl gradient centrifugation. The HA-containing fragments thus obtained were further digested with chondroitinase AC II and subjected to TSK gel high performance liquid chromatography (HPLC). Peptide-HA disaccharide-containing fractions (the SHAP.HA binding regions) were further purified by reverse phase HPLC. Major peaks were analyzed by protein sequencing and mass spectrometry (electrospray ionization mass spectrometry and collision induced dissociation-MS/MS). By comparison with the reported C-terminal sequences of the human ITI family, the peptides were found to correspond to tetrapeptides derived from the C termini of heavy chains 1 of and 2 of inter-alpha-trypsin inhibitor (HC1 and HC2), and heavy chain 3 of pre-alpha-trypsin inhibitor (HC3), respectively, and a heptapeptide from HC1. Mass spectrometric analyses suggested that the C-terminal Asp of each heavy chain was esterified to the C6-hydroxyl group of an internal N-acetylglucosamine of HA chain. This report is the first demonstration to give evidence for the covalent binding of proteins to HA.
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PMID:Evidence for the covalent binding of SHAP, heavy chains of inter-alpha-trypsin inhibitor, to hyaluronan. 759 91