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M C van der Heijden

Publications and source records attributed to M C van der Heijden.

12 recordsLinked to original sources
PubMed1991

Partial characterization of protein tyrosine kinase activity in normal and leukemic human myeloid cells.

We have examined the expression of the protein tyrosine kinase (PTK) encoding oncogenes fes and abl in normal and malignant human myeloid cells in immunoblotting experiments. fes was markedly present in all cytosolic and most membrane fractions of normal and malignant cells. abl was only visible in normal cells, and occurred mostly in the cytosolic fractions. Molecular weights of identified proteins were different from the known products of fes and abl, possibly by alternative splicing at the mRNA level or by proteolysis. PTKs in myeloid cells were further purified by fast liquid protein chromatography (FPLC). PTK-activities of column fractions were assayed using a solid-phase non-radioactive dot-blot assay. Cytosolic and membrane fractions showed a FPLC pattern with a constant as well as a variable part in both normal and malignant cells, possibly indicative for PTKs with specialized functions in normal cell growth and transformation. Partial characterization of PTKs from different eluted peaks of AML-M4 blast cells demonstrated that PTKs from these peaks are kinetically distinct from each other.

Cell Membrane↗
PubMed1990

Phosphorylation of pyruvate kinase type K in human gliomas by a cyclic adenosine 5'-monophosphate-independent protein kinase.

In recent years, we reported the isozyme shift of pyruvate kinase from the M- toward the K-type in human neuroectodermal tumors. To investigate whether this shift enables phosphorylation of pyruvate kinase in these tumors, we studied 29 different specimens of human brain tumors for endogenous pyruvate kinase phosphorylation. While in normal human brain no phosphorylation of pyruvate kinase was detected, in all brain tumors pyruvate kinase became phosphorylated. There was no correlation between the extent of the pyruvate kinase phosphorylation and the histological classification and grading or the pyruvate kinase isozyme composition of the tumors. Only pyruvate kinase type K, and not type M, served as a substrate in the phosphorylation reaction. The phosphorylation of pyruvate kinase could be completely inhibited by addition of fructose 1,6-bisphosphate, a positive effector of pyruvate kinase type K; alanine, however, a negative effector, and phospho-enol-pyruvate, a substrate in the pyruvate kinase reaction, had no effect. While pyruvate kinase type L in liver is phosphorylated by a cyclic AMP-dependent protein kinase, the incorporation of phosphate into pyruvate kinase in human brain tumors appeared to be cyclic AMP independent and occurred exclusively on serine residues.

Biopsy↗
PubMed1988

Subunit-specific phosphorylation of pyruvate kinase in medullary thyroid carcinomas of the rat.

Pyruvate kinase from anaplastic medullary thyroid carcinomas contains predominantly K-type subunits, whereas pyruvate kinase from differentiated medullary thyroid carcinomas consist of M- and K-type subunits in about equal proportion. In order to analyse the incorporation of phosphate in the respective isozymes after endogenous phosphorylation of cytosolic extracts with [32P]ATP, homotetrameric isozymes as well as heterotetrameric hybrids of differentiated tumors were resolved by affinity chromatography on Blue-Sepharose CL-6B and, if necessary, further purified by immunoprecipitation. SDS-polyacrylamide gel electrophoresis of purified isozymes and subsequent autoradiography showed the incorporation of phosphate in the K4-type isozymes, but not in the other isozymes. The phosphorylation appeared to be cAMP-independent and occurred on a serine residue.

Animals↗
PubMed1986

Phosphofructokinase in normal thyroid tissue and thyroid neoplasms.

Phosphofructokinase (PFK; ATP: D-fructose-6-phosphate transferase, EC 2.7.1.11) was studied in human thyroid carcinomas (n = 16), follicular adenomas (n = 31) and normal thyroid tissue (n = 19). The specific activity in carcinomas (0.129 +/- 0.070) is significantly increased (p less than 0.001) in comparison with phosphofructokinase in normal thyroid tissue (0.028 +/- 0.009). No difference in phosphofructokinase activity seems to exist between follicular, papillary and undifferentiated carcinomas. Specific activities of follicular adenomas are rather heterogeneous. When these tumors were divided into three groups of increasing proliferative activity as judged by histopathological criteria, highest specific activities of phosphofructokinase were found in the group with the highest proliferative activity. The latter group resembles the enzyme activities found in carcinomas. On the other hand specific enzyme activities of the least active tissues were comparable to normal and different from carcinomas. Adenomas show the same isozyme composition as found in normal thyroid tissue. All three isozymes of PFK, M-(muscle)type, L-(liver)type and P-(platelet)type, were present. Phosphofructokinase from papillary carcinomas show a lesser degree of precipitation with anti-M antibodies. A higher amount of platelet type isoenzyme is found in papillary carcinomas compared to follicular and undifferentiated carcinomas. The influence of citrate, an inhibitor of phosphofructokinase, is in agreement with the isozyme composition.

Adenoma↗
PubMed1985

Pyruvate kinase in normal human thyroid tissue and thyroid neoplasms.

Pyruvate kinase (ATP: pyruvate-2-O-phosphotransferase, EC 2.7.1.40) was studied in human thyroid carcinomas (n = 9), follicular adenomas (n = 32), and normal thyroid tissue (n = 12). The specific activity in carcinomas (mean 0.94 +/- 0.44) is significantly increased (P less than 0.0001) in comparison with pyruvate kinase in normal tissue (mean, 0.14 +/- 0.05). Specific activities of follicular adenomas are rather heterogeneous. When these tumors were divided into three groups of increasing proliferative activity as judged by histopathologic criteria, highest specific activities of pyruvate kinase were found in the group with the highest proliferative activity. On the other hand, specific enzyme activities of the least active tissues (colloid-containing follicular adenomas) were comparable to normal. The isoenzyme composition of normal thyroid tissue is characterized by the presence of K4, K3M, and K2M2 types of pyruvate kinase. In carcinomas, mainly K4 and K3M are found. Undifferentiated tumors express more K4 type compared with follicular and papillary carcinomas. Follicular adenomas with high specific activity show the same electrophoretic pattern as found in follicular carcinomas. Pyruvate kinase from malignant tumors is more inhibited by the amino acid L-alanine than the enzyme from normal thyroid tissue as a consequence of the presence of more K subunits in the malignant tissues. The K4 type from normal thyroid tissue is not kinetically different from the K4 type of carcinomas.

Adenoma↗
PubMed1984

Hexokinase, phosphofructokinase and pyruvate kinase isoenzymes in lymphocyte subpopulations.

In order to study the three regulator enzymes of glycolysis, hexokinase (HK), phosphofructokinase (PFK) and pyruvate kinase (PK), in relation to lymphocyte maturation, lymphocytes of different origin were investigated. Lymphocytes from bone marrow, thymus, cord blood, adult peripheral blood and mitogen-stimulated lymphocytes were investigated. The enzyme activities were determined and the isozyme patterns were studied by means of electrophoresis, kinetic measurements and immunoprecipitation. The young lymphocytes from bone marrow and the mitogen-stimulated lymphocytes could be distinguished from the other lymphocytes by a higher residual HK activity in the presence of the inhibitor glucose-1,6-diphosphate. Peripheral blood T lymphocytes differed from non-T lymphocytes in the PK isozymes distribution. All the cells contained PK type K4 and the hybrid K3M. In T cells a smaller amount of the K isozyme was seen than in non-T cells. The PK residual activity in the presence of alanine was significantly higher in peripheral blood T cells than in non-T cells. Thymocytes are characterised by a larger amount of PFK M-subunits than peripheral blood T and non-T lymphocytes. The stimulation of PFK by the positive effector glucose-1,6-diphosphate was higher in thymocytes than in the peripheral blood lymphocytes.

Bone Marrow↗
PubMed1982

Isozyme distribution of hexokinase, phosphofructokinase and pyruvate kinase in lymphocytes from patients with chronic lymphocytic leukemia.

The enzyme activities and isozyme distribution of the three glycolytic regulator enzymes hexokinase, phosphofructokinase and pyruvate kinase were studied in lymphocytes of patients with chronic lymphocytic leukemia. Isozyme distribution patterns were determined by kinetic measurements, electrophoresis and immunoprecipitation. The CLL lymphocytes were different from normal non-T lymphocytes with respect to hexokinase residual activity in the presence of glucose-1,6-P2, pyruvate kinase residual activity in the presence of alanine, and phosphofructokinase activity after stimulation by glucose-1,6-P2. No differences could be discerned in enzyme activities between the CLL and the normal T and non-T lymphocytes.

Hexokinase↗
PubMed1976

Human leucocyte alpha-L-fucosidase.

1. Human alpha-L-fucosidase (EC 3.2.1.51) was studied from leucocytes, urine and serum. 2. The leucocyte and urine enzymes are similar in many properties (KM, pH optimum, electrophoretic pattern, heat stability). 3. The serum alpha-L-fucosidase differs from the leucocyte and 4rine enzyme wit,respect to: electrophoretic pattern, pH optimum and heat stapility. 4. The molecular weight of leucocyte alpha-L-fucosidase was determined to be 80 000 +/- 5000. 5. Cu2+, Hg2+ and PCMB are strong inhibitors of leucocyte alpha-L-fucosidase. This inhibition could be completely reversed by beta-mercaptoethanol, indicating that thiol groups are essential for catalytic activity.

Anions↗
PubMed1976

Characterization of alpha-L-fucosidase from two different families with fucosidosis.

1. Two different families with a different type of fucosidase deficiency are described. 2. In the first family the activity of alpha-L-fucosidase in leucocytes of two patients with fucosidosis type I was about 4 to 8% of the normal value. The activity of alpha-L-fucosidase in the leucocytes of the father and the mother are in the heterozygote range, while a sister of the propositus showed normal values. 3. The activity of alpha-L-fucosidase of the propositus from urine, serum and liver were also severely decreased. The activity of alpha-L-fucosidase in the urine of the parents and the healthy sister of thr propositus were about 5% of the mean normal value. However in the serum these values were above 50%. 4. The KM value for alpha-L-fucosidase from leucocytes of the patient was increased about 10 times and in serum this value was even higher. The KM values from the enzyme of the parents were in the normal range. 5. The abnormal enzyme from the propositus is unique in its thermal behaviour since after heating its activity increased. 6. In the second fanily the activity of alpha-L-fucosidase in the leucocytes of the patient is about 30% of the mean normal value, while the arylsulphatase A activity is also decreased (25% of the mean normal value). 7. The activity of alpha-L-fucosidase from the leucocytes of the father and the healthy brother are about 50% of the mean normal level, while the enzyme of the mother showed a normal activity. 8. The alpha-L-fucosidase activity in the urine and the liver of the propositus is also decreased. The serum enzyme activity however was in the normal range. 9. The KM value of alpha-L-fucosidase and heat stability of the enzyme of the patient were normal. In the leectrophoretic pattern of the whole family one bond was missing.

Acetylglucosaminidase↗
PubMedDate not supplied

Partial characterization of protein tyrosine kinases in human lymphoid cells.

We have examined several aspects of protein tyrosine kinase (PTK)-activity in the cytosolic and membrane fractions of both normal and malignant lymphoid cells. The expression of the PTK-encoding oncogenes fes, abl and src, was investigated with the use of antibodies generated to their respective gene products. These antibodies recognized proteins in all cell types examined, most frequently in both the cytosolic and the membrane fraction. PTKs were partially characterized by FPLC. PTK-activities of column fractions were assayed using a non-radioactive dot blot assay. Cytosolic and membrane fractions showed FPLC patterns with a constant as well as a variable part in both normal and malignant cells, suggestive of PTKs with specialized functions in normal cell growth and transformation. Lastly, using antibodies to phosphotyrosine, we found that cytosolic fractions contained the majority of proteins phosphorylated at tyrosine in all cell types. Normal peripheral blood lymphocytes and B-lymphoma cells showed a great similarity in tyrosine phosphorylation pattern, while in tonsillar lymphocytes a clearly different pattern was found. These methods further characterize PTK-activities in lymphoid cells, and the results give evidence that PTKs in normal and malignant cells have both similar and different aspects.

Cell Membrane↗