Linked Life Data

16545013

Source:http://linkedlifedata.com/resource/pubmed/id/16545013

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2006-3-20
pubmed:abstractText
Serum vitamin D3-binding protein (Gc protein) is the precursor for the principal macrophage-activating factor (MAF). The precursor activity of serum Gc protein was lost or reduced in HIV-infected patients. These patient sera contained alpha-N-acetylgalactosaminidase (Nagalase), which deglycosylates serum Gc protein. Deglycosylated Gc protein cannot be converted to MAF and thus loses MAF precursor activity, leading to immunosuppression. Nagalase in the blood stream of HIV-infected patients was complexed with patient immunoglobulin G, suggesting that this enzyme is immunogenic, seemingly a viral gene product. In fact, Nagalase was inducible by treatment of cultures of HIV-infected patient peripheral blood mononuclear cells with a provirus-inducing agent. This enzyme was immunoprecipitable with polyclonal anti-HIV but not with anticellular constitutive enzyme or with antitumor Nagalase. The kinetic parameters (km value of 1.27 mM and pH optimum of 6.1), of the patient serum Nagalase were distinct from those of constitutive enzyme (km value of 4.83 mM and pH optimum of 4.3). This glycosidase should reside on an envelope protein capable of interacting with cellular membranous O-glycans. Although cloned gp160 exhibited no Nagalase activity, treatment of gp160 with trypsin expressed Nagalase activity, suggesting that proteolytic cleavage of gp160 to generate gp120 and gp41 is required for Nagalase activity. Cloned gp120 exhibited Nagalase activity while cloned gp41 showed no Nagalase activity. Since proteolytic cleavage of protein gp160 is required for expression of both fusion capacity and Nagalase activity, Nagalase seems to be an enzymatic basis for fusion in the infectious process. Therefore, Nagalase appears to play dual roles in viral infectivity and immunosuppression.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0889-2229
pubmed:author
pubmed:issnType
Print
pubmed:volume
22
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
262-71
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Pathogenic significance of alpha-N-acetylgalactosaminidase activity found in the envelope glycoprotein gp160 of human immunodeficiency virus Type 1.
pubmed:affiliation
Division of Molecular Virology, Socrates Institute for Therapeutic Immunology, Philadelphia, Pennsylvania 19126-3305, USA. nobutoyama@peoplepc.com
pubmed:publicationType
Journal Article, Research Support, N.I.H., Extramural