Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.108 (lactase)
 2,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Lactate transport across the sarcolemma of isolated mouse muscles was studied with a 14C tracer technique. The cellular tracer uptake could be inhibited by unlabelled L-lactate (and pyruvate) and to a lesser extent by D-lactase. The stereospecific fraction had a Km of 3.5 mM, and made up 50% of the total transport. The tracer uptake was unaffected by 0.05 mM DIDS and 0.2 mM amiloride, but was inhibited by cinnamate (Ki = 8 mM) and PCMBS (Ki = 0.8 mM). With high concentrations of the latter inhibitor compounds or with high concentrations of unlabelled L-lactate, the tracer uptake was inhibited 80%, which indicates that the main part of the transport involves facilitated diffusion. The remaining fraction (20%) was non-saturable, reduced at high pH, and could not be inhibited; it is probably mediated by diffusion of undissociated lactic acid. Lactate transport was pH-dependent, which is consistent with a lactate-H+ symport. The maximal transport capacity, as calculated from the pH changes measured with pH-sensitive micro-electrodes while the lactate gradient was 30 mM, was 11.8 mmol kg-1 min-1 (pH 6.2).
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PMID:Lactate transport in isolated mouse muscles studied with a tracer technique--kinetics, stereospecificity, pH dependency and maximal capacity. 255 49

Lactate production and oxygen consumption were studied in single cell suspension prepared from solid tumours of the black-melanotic (Ma), brown-melanotic (MI) and amelanotic (Ab) melanomas of hamster. Aerobic lactase production was about 5 times higher in the fast growing Ab melanoma than in the slow growing Ma and MI melanomas. Aerobic lactate production in both melanotic hamster melanomas was stimulated by 3-(3,4-dihydroxyphenyl)-L-alanine. This compound was without effect on the cells isolated from amelanotic hamster melanoma. L-Phenylalanine, a known competitive tyrosinase inhibitor reduced the stimulatory effect of L-DOPA on the the lactate production. Oxygen consumption was similar in all three melanomas. The oxygen consumption was inhibited completely by 1 mM potassium cyanide in the Ab melanoma but only in about 1/3 in the Ma and MI melanomas. The Pasteur effect was higher in relative terms and lower in absolute terms in the melanotic melanomas than in the Ab melanoma only . The Crabtree effect was present in the Ab melanoma only. Thus glycolysis measured by aerobic and anaerobic lactic acid formation, and cell respiration, measured by oxygen consumption sensitive to KCN, were both higher in the more malignant, less differentiated Ab melanoma than in the Ma and MI melanomas. The suggestion is presented that the process of melanogenesis influences both aerobic glycolysis and the KCN insensitive consumption in the melanotic hamster melanomas.
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PMID:Biochemical characterization of three hamster melanoma variants--II. Glycolysis and oxygen consumption. 669 97

This study was conducted to determine whether bathing in tepid water is effective in facilitating recovery from fatigue after submaximal exercise. Subjects were six young healthy male university students. Following cycle exercise at 80% aerobic power (VO2 max) for 10 min, recovery was observed during and after 10-min bathing. Three conditions were set; (1) water temperature of 38 degrees C, (2) water temperature of 30 degrees C, and (3) no water in the bath tub (control). Measurements were heart rate, blood pressure, skin temperature, rectal temperature, blood lactase and subjective feelings. There were no significant differences in heart rate and blood pressure between the three conditions at any time. Mean skin temperature and rectal temperature decreased more rapidly after the 30 degrees C bathing than the other two conditions (p < 0.05). Lactate removal was largest for the 30 degrees C bathing, with significant difference between the 30 degrees C bathing condition and the no bathing condition (p < 0.05). Recovery from fatigue was best for the 30 degrees C bathing and worst for the control in terms of subjective feeling. In summary, it was shown that immersion in 30 degrees C water after submaximal exercise resulted in a larger removal of lactate than recovery in air.
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PMID:Effects of immersion in tepid bath water on recovery from fatigue after submaximal exercise in man. 885 30