Search PubMed⌕ Search

Biomedical subjects

W Kuhl

Publications and source records attributed to W Kuhl.

At least 73 records · Page 4Linked to original sources
PubMed1977

Enzyme replacement therapy in Gaucher's disease: preliminary clinical trial of a new enzyme preparation.

A patient with far-advanced adult type Gaucher's disease was treated with solubilized, highly purified placental glucocerebrosidase administered after entrapment in human erythrocytes or by direct intravenous injection. In some instances the enzyme-containing erythrocytes were coated with gamma globulin. No toxic side effects were observed after enzyme infusion. There were suggestive, but not conclusive, findings that enzyme infusion may have been beneficial. After therapy, there was a decrease in transfusion requirement, some improvement of liver function, possible decrease in liver size, and relief of subjective symptoms. Erythrocyte and plasma glucocerebroside levels were unchanged during therapy, but there was a possibly significant decrease in leukocyte and platelet levels of the glycolipid. No changes occurred in serum acid phosphatase or angiotensin-converting enzyme activity.

Acid Phosphatase↗
PubMed1977

The tissue distribution of hexosaminidase S and hexosaminidase C.

The proportion of hex S to hex C in normal and Sandhoff's fibroblasts was determined to be between 1:1 and 1:2 by differential staining of hex S at pH 4.4 with 4-methylumbelliferyl-beta-N-acetylgalactosaminide and of hex C at pH 7.0 with 4-methylumbelliferyl-beta-N-acetylglucosaminide. Hex S and hex C were also semi-quantitated in various normal tissues--brain, liver, spleen, heart, kidney, intestine, placenta, skeletal muscle and fibroblasts. Hex C was most prominent in brain and, somewhat less so, in liver, skeletal muscle and fibroblasts. The greatest amount of hex S activity was found in fibroblast, but it was also observed in lesser amounts in liver, kidney, intestine and placenta.

Electrophoresis↗
PubMed1976

The subunits of human hexosaminidase A.

Previous studies of the subunit structure of hexosaminidase gave ambiguous results, but suggested that the enzyme was composed of six equally sized subunits. Dissociation of hexosaminidase A with p-chloromercuribenzoate produces an alkylated fragment with mol.wt. approx. 50000, which is converted into hexosaminidase S by treatment with dithiothreitol. Treatment of native hexosaminidase A with sodium dodecylsulphate results in the formation of a large and a small fragment. However, although the native enzyme has a sedimentation coefficient of 5.8S, dissociation by S-carboxymethylation and maleic anhydride treatment results in subunits exhibiting a single schlieren boundary on analytical ultracentrifugation with a sedimentation coefficient of 2.18S. These results indicate that the enzyme is composed of four subunits, each with molwt. approx. 25000-27000. The mol.wt. of the native enzymes is calculated to be approx. 110000. Our data are consistent with the subunit structures of hexosaminidases A, B and S as being alpha2beta2, beta4 and alpha4 respectively.

Electrophoresis, Polyacrylamide Gel↗
PubMed1976

Acid hydrolases in leukocytes and platelets of normal subjects and in patients with Gaucher's and Fabry's disease.

Lymphocytes, monocytes, neutrophilic granulocytes and platelets were each separated to greater than 95% purity from six normal subjects, three patients with Gaucher's disease, two heterozygotes for Gaucher's disease, and one patient with Fabry's disease. Activities of the following acid hydrolases were determined: "acid" (pH 4.0) beta-glucosidase, pH 5.0 beta-glucosidase, alpha-galactosidase, alpha-arabinosidase, alpha-mannosidase, alpha-glucosidase, beta-glucuronidase, beta-galactosidase, beta-hexosaminidase, and acid phosphatase. Enzymatic activity varied greatly with cell type and the enzyme being measured; the importance of assaying pure preparations especially for heterozygote detection is emphasized. Gaucher's disease patients' cells were found to be deficient in the pH 4.0 acid beta-glucosidase, variable in the pH 5.0 beta-glucosidase, and normal in all other acid hydrolases tested, including acid phosphatase, the activity of which is known to be elevated in plasma. Blood cells of a patient with Fabry's disease were deficient in alpha-galactosidase and normal in all other acid hydrolases tested.

Acid Phosphatase↗
PubMed1976

Characterization of heteropolymeric hexosaminidase A in human X mouse hybrid cells.

Expression of heteropolymeric hexosaminidase A activity is reported in a human X mouse hybrid cell line that contains an X/15 translocation chromosome but lacks human chromosome 5 and has no detectable human hexosaminidase B activity. (Hexosaminidase is beta-N-acetylglucosaminidase; EC 3.2.1.30; 2-acetamido-2-deoxy-beta-D-glucoside acetamidodeoxyglucohydrolase.) That the "hexosaminidase A" enzyme of these cells contains the human hexosaminidase-alpha subunit and not the human hexosaminidase-beta subunit is indicated by the cells' reactions to specific antisera prepared against the alpha subunit and against the beta subunit. Our results indicate that the "hexosaminidase A" activity in this hybrid cell line is the expression of a hybrid molecule composed of human hexosaminidase-alpha subunit and a mouse hexosaminidase subunit. These results are consistent with the hypothesis that the human hexosaminidase A enzyme is formed from alpha and beta subunits coded for by genes on chromosomes 15 and 5, respectively.

Animals↗
PubMed1975

Placental acid hydrolase purification on concanavalin A-sepharose.

Crude human placental extract was chromatographed on concanavalin A-Sepharose. Using a single procedure, 20- to over 300-fold purification of six acid glycohydrolases was achieved, in most cases with a good yield. Improved yield of individual enzymes could be achieved by modifications of the method of elution. The capacity of concanavalin A-Sepharose to bind glycohydrolases from placenta was very large, and will provice a useful procedure for the large-scale purification of the human enzymes.

Chromatography↗
PubMed1975

Nonenzymatic conversion of human hexosaminidase A.

Incubation of purified hexosaminidase A with merthiolate, parahydroxymercuribenzoic acid, or silver ions resulted in the formation of an enzyme which was identical, in all respects tested, with hexosaminidase B. Its electrophoretic mobility was identical to hexasaminidase B at three different pH levels. Its chromatographic properties, thermostability, and immunologic reactivity with specific anti-hexosaminidase A and anti-hexosaminidase B antisera were indistinguishable from hexosaminidase B. Conversion could be prevented by GSH but was not reversed by GSH once it had occurred. Conversion of hexosaminidase A to hexosaminindase B was accompanied by the appearance of an electrophoretically rapid, catalytically inactive protein. Hexosaminidase B, itself, was unaltered by incubation with merthiolate. These findings support a previously proposed model of hexosaminidase structure in which hexosaminidase A is (alphabeta)3 and hexosamindase B is (betabeta)2. On treatment of hexosaminidase A with merthiolate and other converting agents alpha and beta subunits are presumably dissociated and they reassociate as (betabeta)3, that is, hexosaminidase B. The expected free or polymerized catalytically inactive, alpha chains are detected on acrylamide gel electrophoresis. We suggest that the catalytic site of human hexosaminidase may be present only on the beta subunit and that the alpha subunit influences the substrate specificity of the enzyme, particularly as directed toward GM2.

Chromatography↗
PubMed1975

Hexosaminidase isozyme in type O Gm2 gangliosidosis (Sandhoff-Jatzkewitz disease).

The residual enzyme of the fibroblasts of a child with homozygous type 0 GM2 gangliosidosis (Sandhoff-Jatzkewitz disease) has been found to correspond with a minor fraction of enzyme which can be isolated from normal fibroblasts by repeated chromatography. This enzyme is designated as hexosaminidase (hex) S. It reacts with antiserum prepared against homogeneous hex A but not with serum prepared against homogeneous hex B. These findings support our previously described model of the relationship between hex A and hex G: hex A has the structure (alpha beta)3, while hex B is (beta)6. Type B GM2 gangliosidosis (Tay-Sachs disease) is the alpha- mutation, while type 0 GM2 gangliosidosis (Sandhoff-Jatzkewitz disease) is the beta- mutation. In the absence of normal beta subunits there is increased polymerization of alpha subunits forming hex S, which probably has a structure of (alpha)6. A parallel between the thalassemias and GM2 gangliosidosis is evident: deficiency of one of the chains of which the protein is composed leads to an excess of polymers comprised of the other chains. In type B GM2 gangliosidosis, the excess of beta chanis leads to increased amounts of hex B beta)6; in type 0 GM2 gangliosidosis, the excess of alpha chains leads to formation of increased amounts of the alpha chain polymer, hex S.

Antigens↗