Some comparative properties of pyruvate kinase in haematopoietic cells and erythrocytes from rainbow trout (Salmo gairdneri R)

1. Temperature acts as a pyruvate kinase regulator in haematopoietic cells and erythrocytes. 2. Fructose-1,6-biphosphate and alanine act as allosteric modulators of pyruvate kinase in haematopoietic cells, while in erythrocytes although fructose-1,6-biphosphate exerts also allosteric effect, alanine appears to be a competitive inhibitor. ATP (1.0 mM) does not exert any clear effect on pyruvate kinase of both cellular populations. 3. The level of specific activity of pyruvate kinase in haematopoietic cells is 40-fold that of PK from erythrocytes.

Cytoimmunochemical study of pyruvate kinase isoenzymes in rat liver

Using immunofluorescence and double-labelled antisera L and M pyruvate kinase (PK), we show that PK is localized in hepatocyte cytoplasm. The response is modulated by different dietary and hormonal conditions. In physiological conditions, only L PK is noted: slight with normal diet (or 35 micrograms of glucagon) and non-existent with starvation (or 350 micrograms of glucagon). L PK fluorescence is maximal after a carbohydrate-rich diet. In experimental or genetic (Zucker rat) hyperinsulinemia, hepatocytes are both L PK and M PK positive. After partial hepatectomy, this double specificity is found between 48 h and the 7th day. The decrease of PK fluorescence after starvation or glucagon concerns the L PK form of the enzyme. With exo- or endogenous insulin, the increase of PK (as insulinemia assays from Zucker rats or after partial hepatectomy confirm) is essentially due to the presence of M PK in hepatocytes.

A logistic model based on enzyme activities for the prediction of response of breast cancer patients to chemotherapy

A logistic regression model, utilizing the activities of certain selected glycolytic enzymes and ER status measured on primary or recurrent lesions, has been applied to predict for response to combination chemotherapy regimens administered to women with advanced breast cancer. The clinical outcome of response or no response was evaluated retrospectively using criteria employed by cooperative group protocols. In 93 cases, 58/61 patients classified as nonresponders and 22/32 patients demonstrating objective responses would have been correctly designated, based on the 50% estimated probability as the level for separation of responders from nonresponders. The overall predictive accuracy of this model was 86%, with apparently greater accuracy for prediction of lack of response. Addition of estrogen receptor status to the model imparted no gain in accuracy of prediction. Application of this model to a prospective study is warranted.

Pyruvate-kinase (PK) and creatine-kinase (CK) in normal pregnancy and its implication in genetic counseling of Duchenne muscular dystrophy (DMD)

The activities of pyruvate-kinase (PK) and creatine-kinase (CK) were measured in 50 normal pregnant women in both serum and amniotic fluid. Serum PK activity was found to be significantly higher in pregnant than in nonpregnant women, while serum CK did not differ significantly between the two population samples. In amniotic fluid, very little or no PK or CK activity was found. However, the mean PK activity in amniotic fluid obtained from women carrying male fetuses was significantly higher than in those carrying female fetuses. At the present time, it is concluded that if a woman at risk for having a son with Duchenne dystrophy is seeking genetic counseling when already pregnant her serum PK or CK should be compared with that of normal female pregnant controls. It is also suggested that determination of pyruvate-kinase in fetal blood might be used in addition to CK for prenatal diagnosis of Duchenne muscular dystrophy.

Pyruvate kinase deficiency anaemia in a Basenji dog

Pyruvate kinase deficiency anaemia was suspected in an 18-month-old male Basenji dog after other known causes of canine haemolytic anaemia had been excluded. Anaemia of moderate severity (packed cell volumes 0.20 to 0.26 1/1) and reticulocytosis (uncorrected reticulocyte counts 8 to 43%) persisted during 5 months' observation, and biopsies showed development of bone marrow fibrosis and sclerosis. The diagnosis of pyruvate kinase deficiency anaemia was presumptive because erythrocyte pyruvate kinase concentrations in the affected dog were inconclusive and related animals were not available for enzyme assay. However, the gene for pyruvate kinase deficiency is known to occur among Basenji dogs in Australia.

Immunocytochemical study of pyruvate kinase isoenzymes in normal and pathologic human liver

In healthy human livers, L pyruvate kinase (L PK) was detected by immunofluorescence and double labelling in hepatocytes and M PK was detected in bile duct epithelial cells. Numerous associations between isoenzyme type and hepatological lesion were observed. In 10 cases of ethanolic cirrhosis, L and M PK were simultaneously observed in the hepatocytes of regenerative nodules, as they were in biliary neoductules; fibrotic regions were L and M PK negative and the hepatocytes in the anastomosing plate system were almost exclusively L PK positive, as in normal subjects. In 12 hepatocarcinomas, cancer cells had a double L and M specificity with variations in the intensity of the M isoenzyme, while the stroma reaction was L and M negative. In five hepatoblastomas, the simultaneous presence of L and M PK was also observed, but the consistently marked intensity of M PK argues in favour of the embryonic nature of this type of cancer. The results suggest that mature, highly differentiated cells exclusively and specifically synthesize one isoenzyme. A double specificity in pathology reflects the dysfunctional state of the hepatic and biliary epithelial cells or a dedifferentiated state which may terminate with the appearance of a cancer.

Peptide structures of pyruvate kinase isozymes: 2. Origins of types M1 and M2 isozymes suggested from species-variations in their peptide maps

Pyruvate kinase (ATP:pyruvate 2-O-phosphotransferase, EC 2.7.1.40) isozymes were purified: type M1 and M2 isozymes from rat, mouse and rabbit, type M1 from bull frog and type L from rat and mouse. The amino acid composition of type M1 and M2 isozymes from various species were very similar and those of type L isozymes from rat and mouse also very similar. The NH2-terminals to type M1 and M2 from rat and mouse were (Pro-Lys-Pro-), but those of the other enzymes appeared to be blocked. The COOH-terminals of type M1 and M2 from rat, mouse and rabbit were (-Val-Pro). Comparison of tryptic peptide maps of type M1 and M2 from rat, mouse and rabbit indicated that type M1 and M2 could not be produced by post-synthesis modification, but could be encoded by different type-specific mRNAs. Comparative studies on type M1 and M2 of different species showed that type M1-specific peptide spots were highly variable, whereas type M2-specific peptide spots were highly conserved. The type L isozyme showed marked species variation, indicating that this differentiated isozyme evolved more rapidly than type M2, which may be a prototype or undifferentiated isozyme.

Pyruvate kinase and phosphofructokinase isozymes in childhood cancers

Pyruvate kinase and phosphofructokinase isozymic expression have been investigated in 62 childhood cancers by electrofocusing and immunoneutralization. Isozymic expression was roughly intermediate between that of the corresponding normal adult and fetal tissue. There were unique features distinguishing malignant from both adult and fetal tissues. In addition, phosphofructokinase and pyruvate kinase appeared to be excellent markers for nervous tissue and skeletal muscle differentiation. In neuroblastomas there was a close relationship between the differentiation level of tumors and their isozyme composition. The same phenomenon was observed in rhabdomyosarcomas and teratomas.

Supplementing glucose metabolism in human senile cataracts

Assay of the activities of hexokinase, phosphofructokinase, and pyruvate kinase showed that the first two declined in aging human lens cortex and all three enzymes retained constant activities in the epithelium throughout life. Moreover, both clear and cataractous aging lenses contained the same enzyme activities. ATP contents in cataracts, however, were lower than in clear lenses; in fact, after incubation at 37.5 degrees C in isotonic (290 to 300 mOsm), glucose-containing media, ATP was rapidly lost from cataracts (but not from clear lenses), suggesting excessive ATP expenditure in cataracts for osmotic balance. Cataracts incubated in media containing either glucose-6-phosphate or fructose-1, 6-diphosphate produced significantly higher ATP than with glucose in the media, indicating that glucose metabolism in human senile cataracts could be supplemented with hexose phosphates. Fructose-1, 6-diphosphate appeared to be more efficient than glucose-6-phosphate in preventing lens swelling during incubation.

The aldolase and pyruvate kinase isoenzyme patterns in a malignant testicular tumor from a 27 year old male

On the basis of performed tests, we observed the change of pattern of pyruvate kinase isoenzyme in a malignant testicular tumor (only isoenzyme K) and the same isoenzyme in the tissue of other testis not being tumorously changed. In control group pyruvate kinase isoenzyme K and M was observed. Similarly, another pattern of aldolase isoenzymes in tumorous tissue was stated (AC) comparing with control group (arrangement AC, BC). The changes referred also to the activity of both examined enzymes in tumorous tissue and in the tissue of testis not being tumorously changed. The authors suggest the existence of a factor with depressor characteristics, which is produced by neoplasm and changes the function of genes that are responsible for synthesis examined isoenzymes in the tissue not being tumorously changed.

Bioenergetic alterations in cultivated pulmonary artery and aortic endothelial cells exposed to normoxia and hypoxia

Endothelial cells function under conditions of different oxygen availability under physiologic conditions and a variety of pathologic states. We determined the effect of normal and low O2 tensions on three key bioenergetic enzymes [pyruvate kinase (ATP:pyruvate phosphotransferase, EC 2.7.1.40), phosphofructokinase (ATP:D-fructose-6-phosphate 1-phosphotransferase, EC 27.1.11) and cytochrome aa3] in culture-maintained endothelial cells derived from calf pulmonary artery and aorta. Endothelial cells derived from pulmonary artery and aorta demonstrate similar bioenergetic enzyme activities when exposed to the same PO2 in vitro. Endothelial cells exposed to hypoxia in vitro for 48-96 hr show significantly increase activities of 2 key glycolytic enzymes: pyruvate kinase, and phosphofructokinase. Freshly isolated intimal strips from calf pulmonary artery (normal PO2 = 40 torr) show significantly greater activities of PyKi than aortic intimal strips (normal PO2 = 90 torr), suggesting that a similar pattern occurs in vivo. The data suggest that both cell types have a common bioenergetic pattern which is genetically determined and that this pattern is modified by regulatory mechanisms geared to ambient O2 tension. As endothelial cells of both types are not uncommonly exposed to hypoxic conditions, these regulatory mechanisms may play an important role in maintaining vascular integrity.

Low tissue enzyme activity seen in breast cancers of patients who fail adjuvant chemotherapy

Primary breast cancers from 54 patients undergoing postsurgical adjuvant chemotherapy were analyzed for several enzymes and estrogen receptors to determine if biochemical parameters might offer a prognostic index for determining outcome of therapy. Recurrence of disease during therapy or within 12 months after cessation of therapy was the criterion for classifying the patient as a treatment failure. Recurrence rates were similar in ER-positive vs. ER-negative patients, indicating that estrogen receptor status offered no predictive value in this series. However, patients who failed therapy had tumors that displayed significantly lower activities of lactate dehydrogenase, glucosephosphate isomerase, and glucose 6-phosphate dehydrogenase vs. patients who showed no evidence of recurrence for this observation period. When either premenopausal or ER-negative patients were compared, a similar observation was made; low enzyme activities occurred in patients failing to benefit from adjuvant chemotherapy. Based on this series of patients, it is suggested that a selected enzyme activity profile may offer a predictive index for recurrence in the adjuvant chemotherapy setting.

Purification and properties of mouse pyruvate kinases K and M and of a modified K subunit

The K4 and M4 isozymes of mouse pyruvate kinase were purified to homogeneity, and their physical, chemical, and kinetic properties were compared. The K isozyme is slightly larger, but a high degree of homology exists as evidenced by a similar amino acid composition, immunotitration value, and two-dimensional arginine peptide pattern after tryptic digestion. Also, the more active conformational form of the K isozyme has kinetic and chromatographic properties similar to those of the M isozyme. Only K subunit could be extracted with antibody from fresh spleen extracts, but this subunit can be cleaved to form a product with the mobility of the M subunit. The cleavage is accomplished by an endogenous enzyme and appears to be the first step in K-enzyme degradation. This product is called Kpm . KpmK hybrid could also be purified to homogeneity. This enzyme has the structure K2pmK2, and both types of subunit have activity. The Kpm form has a higher K0.5S value for phosphoenolpyruvate and a lower K0.5S value for ADP than does either the K or the M type. However, the Kpm and M subunits otherwise have very similar properties and it is speculated that the Kpm subunit is an M-type precursor.

[Localization of pyruvate kinase M1 (ATP pyruvate phosphotransferase-2.7.1.40) in nervous tissue of the rat. Preliminary results]

The M1 pyruvate kinase has been localized in macroneuron's cytoplasm of nervous tissue of adult Rat, in situ as well as in tissue culture. Three methods have been used: histoenzymology, immunoenzymology and immunofluorescence, combined with Nomarski optics. This enzymatic localization may suggest a metabolic or differenciated fonctionnal state of the nerve cell.

Ultrastructural and biochemical alterations in the livers from chick embryos maintained in shell-less culture

Ultrastructural and biochemical studies were conducted on the livers from chick embryos maintained in shell-less culture up to stage 39 (Hamburger-Hamilton) and from control embryos developed in ovo up to the same stage. The ultrastructural characteristics of hepatic cells from the cultured embryos were similar to those found in the controls except that they contained many large lipid droplets and were almost devoid of lipoprotein granules normally associated with the Golgi complex and the smooth endoplasmic reticulum. These changes suggest the existence of alterations in the lipid metabolism. The livers from cultured embryos showed also a decreased incorporation of tritiated leucine into proteins, which indicates a reduced rate of protein synthesis. These results are consistent with previous reports showing that cultured embryos possess hypoproteinemia. Lactic dehydrogenase activity was similar and pyruvic kinase higher in the livers from cultured with respect to control embryos. This appears to indicate that both aerobic and anaerobic glycolysis were not depressed and that the changes observed in the rate of protein synthesis should not be attributed to hypoxia. "Fat-storing cells" similar to those described in mammals were found both in control and cultured embryos. They had not been previously described in the livers from chick embryos.

Isozyme patterns of pyruvate kinase and differentiation of Friend leukemia cells

The isozyme patterns of glycolytic enzymes of Friend leukemia cells (FLC) were compared with those of erythrocytes and erythroblasts. Erythrocyte-specific R types of pyruvate kinase (PK) were clearly observed in phenylhydrazine-induced mouse erythroblast, and much less amount of them was also observed in Friend leukemia cells. When FLC were induced to differentiate by hexamethylene-bisacetamide (HMBA), the R types were slightly reduced. When the induction of differentiation was inhibited by 12-O-tetradecanoylphorbol 13-acetate (TPA), the R types and M2-R hybrids rather increased. These results are reverse of those obtained when hemoglobin production is used as a marker of differentiation. Isozyme patterns of lactic dehydrogenase and aldolase did not change during differentiation of FLC induced by HMBA, and were the same as those of mouse erythroblasts and erythrocytes.

[Epithelial localization of pyruvate kinase L (ATP pyruvate phosphotransferase EC 2.7.1.40) in rat liver]

Using three methods: histoenzymatic and immunoenzymatic, stained with tetrazolium salt, and immunofluorescence, we have localized PK "L" in hepatocytes. This localization in the cytoplasm of the cells differs widely in intensity with diet or hormone administration. Maximal with animals fed on high carbohydrate diet, still elevated with a subsequent insulin administration, it decreases with a normal diet to become weaker in animals, which have fasted for 48 hrs.