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J P de Geus

Publications and source records attributed to J P de Geus.

7 recordsLinked to original sources
PubMed1989

The primary structure of a feline class I gene: striking similarity to HLA-A.

The sequence of a feline class I pseudogene and its comparison with class I genes from other species is presented. The gene isolated is a pseudogene because of the presence of four stop codons and two frame shift mutations in the first- and second-domain encoding exons, as well as a mutation in a splice acceptor site in the third intron. By sequence comparison with the other class I sequences determined to date, the FLA pseudogene is most closely related to the HLA-A locus products (88% nucleotide identity.

Amino Acid Sequence↗
PubMed1988

Immunoreactive epitopes on human retinal S-antigen.

Although retinal S-antigen can induce experimental auto-immune uveitis in various animal species including primates, its role in clinical uveitis is not exactly known. More detailed knowledge on the immunoreactivity of human S-antigen might be of importance, since bovine S-antigen has been shown to carry both uveitogenic and non-uveitogenic epitopes. The number of immunoreactive epitopes on purified human S-antigen was therefore investigated in an inhibition ELISA with the use of a panel of four polyclonal and two monoclonal immune reagents. Assessment of their capacity to compete with each other for binding to the antigen resulted in complete, partial or no inhibition in the various combinations tested. Rabbit and rat anti-S-antigen immunoglobulins inhibited each other partially (up to 60%), from which the existence of at least three (groups of) epitopes was derived. Two monoclonal antibodies, of mouse (PDS-1) and rat (S.2.4C5) origin, did not inhibit each other, and thus defined two separate epitopes on human S-antigen. These epitopes belong to the set recognized by both rabbit and rat anti-S-antigen immunoglobulins since both monoclonals could be inhibited by rabbit and by rat antibodies. Epitopes detected by two mouse antisera also appeared to belong to this set. Thus, the existence of at least four immunoreactive sites on human S-antigen could be demonstrated.

Antibodies, Monoclonal↗
PubMed1986

Binding and hydrolysis of 2-azido-ATP and 8-azido-ATP by isolated mitochondrial F1: characterisation of high-affinity binding sites.

The kinetic parameters for the hydrolysis by F1 of the photoreactive nucleotide analogue 2-azido-ATP were determined (Vmax, 105 U/mg F1; Km, 250 microM, in the presence of 1.0 mM SO2-3). In the absence of an activating anion, a non-linear relationship in a Lineweaver-Burk plot was found for the hydrolysis of 2-azido-ATP. The 2-azido-analogues of ATP and ADP proved to be good photoaffinity labels causing notable inactivation of the F1-ATPase activity upon irradiation at 360 nm. This inhibition was also used to demonstrate high-affinity binding of these analogues to a catalytic binding site on the F1. High-affinity binding proved to be an Mg2+-requiring process, occurring with both 2-azido-ATP and 2-azido-ADP but hardly or not occurring with 8-azido-AT(D)P. Covalent binding of 2-nitreno-ATP upon irradiation of F1 containing tightly bound [beta-32P]2-azido-ATP results in a proportional inhibition of ATPase activity, extrapolating to 0.92 mol of covalently bound label per mol of F1 needed for the complete inactivation of the enzyme. When the F1 was irradiated in the presence of excess [beta-32P]2-azido-AT(D)P, 3-4 mol of label were bound when the enzyme was fully inactivated. In all cases, all or most of the radioactivity was found on the beta subunits.

Adenosine Triphosphate↗