Wiesmann UN, DiDonato S, Herschkowitz NN. Effect of chloroquine on cultured fibroblasts: release of lysosomal hydrolases and inhibition of their uptake. Biochem Biophys Res Commun. 1975;66 (4) :1338-43.
Garner CW, Behal FJ. Effect of pH on substrate and inhibitor kinetic constants of human liver alanine aminopeptidase. Evidence for two ionizable active center groups. Biochemistry. 1975;14 (23) :5084-8.Abstract
The presence of at least two ionizable active center groups has been detected by a study of the effect of pH upon catalysis of hydrolysis of L-alanyl-beta-naphthylamide by human liver alanine aminopeptidase and upon the inhibition of hydrolysis by inhibitors and substrate analogs. Octanoic acid, octylamine, and peptide inhibitors have been found to be competitive inhibitors and are therefore thought to bind the active center. L-Phe was previously shown to bind the active center since it was found to be a competitive inhibitor of the hydrolysis of tripeptide substrates (Garner, C. W., and Behal, F. J. (1975), Biochemistry 14, 3208). A plot of pKm vs. pH for the substrate L-Ala-beta-naphthylamide showed that binding decreased below pH 5.9 and above 7.5, the points at which the theoretical curve undergoes an integral change in slope. These points are interpreted as the pKa either of substrate ionizable groups or binding-dependent enzyme active center groups. Similar plots of pKm vs. pH for L-alanyl-p-nitroanilide (as substrate) and pKi vs. pH for L-Leu-L-Leu-L-Leu and D-Leu-L-Tyr (as inhibitors) gave pairs fo pKa values of 5.8 and 7.4, 6.0 and 7.5, and 5.7 and 7.5, respectively. All the above substrates (and D-Leu-L-Tyr) have pKa values near 7.5; therefore, the binding-dependent group with a pKa value near 7.5 is possibly this substrate group. Similar plots of pKi vs. pH for the inhibitors L-Phe, L-Met, L-Leu, octylamine, and octanoic acid had only one bending point at 7.7, 7.6, 7.4, 6.3, and 5.9, respectively. Amino acid inhibitors, octylamine, and octanoic acid have no groups with pKa values between 5 and 9. These data indicate that there are two active center ionizable groups with pKa values of approximately 6.0 and 7.5 which are involved in substrate binding or inhibitory amino acid binding but not in catalysis since Vmax was constant at all pH values tested.
Valentin N, Rasmussen SM. Plasma potassium and insulin during extracorporeal circulation using a glucose-containing pump prime. Scand J Thorac Cardiovasc Surg. 1975;9 (3) :169-74.Abstract
In order to investigate the possible relationship between a glucose-containing pump prime and changes in plasma potassium during extracorporeal circulation, determinations were made of blood glucose and plasma insulin, potassium, and magnesium in 18 subjects undergoing open-heart surgery. In 6 of the patients, the same parameters had been measured during a pre-operative glucose tolerance test. It was found that the elimination of glucose was considerably impaired during extracorporeal circulation, in spite of high insulin levels. During the first minutes of extracorporeal circulation, plasma potassium fell more than during the glucose tolerance test, in spite of comparable insulin levels. It is concluded that changes in plasma potassium during extracorporeal circulation do not reflect insulin activity to any noticeable extent.
Chow YW, Pietranico R, Mukerji A. Studies of oxygen binding energy to hemoglobin molecule. Biochem Biophys Res Commun. 1975;66 (4) :1424-31.
Myers NA, Officer CB. Undescended testis: congenital or acquired?. Aust Paediatr J. 1975;11 (2) :76-80.
Isaac O, Thiemer K. [Biochemical studies on camomile components/III. In vitro studies about the antipeptic activity of (--)-alpha-bisabolol (author's transl)]. Arzneimittelforschung. 1975;25 (9) :1352-4.Abstract
(--)-alpha-Bisabolol has a primary antipeptic action depending on dosage, which is not caused by an alteration of the pH-value. The proteolytic activity of pepsin is reduced by 50 percent through addition of bisabolol in the ratio of 1/0.5. The antipeptic action of bisabolol only occurs in case of direct contact. In case of a previous contact with the substrate, the inhibiting effect is lost.
Bose KS, Sarma RH. Delineation of the intimate details of the backbone conformation of pyridine nucleotide coenzymes in aqueous solution. Biochem Biophys Res Commun. 1975;66 (4) :1173-9.
Schmoldt A, Benthe HF, Haberland G. Digitoxin metabolism by rat liver microsomes. Biochem Pharmacol. 1975;24 (17) :1639-41.
Stein JM. The effect of adrenaline and of alpha- and beta-adrenergic blocking agents on ATP concentration and on incorporation of 32Pi into ATP in rat fat cells. Biochem Pharmacol. 1975;24 (18) :1659-62.
Suzuki T, Uchiyama M. Inhibitory effect of parathion on the photosynthetic electron transport system in isolated spinach chloroplasts. Bull Environ Contam Toxicol. 1975;14 (5) :552-7.
Smith RJ, Bryant RG. Metal substitutions incarbonic anhydrase: a halide ion probe study. Biochem Biophys Res Commun. 1975;66 (4) :1281-6.
Heazell MA. Proceedings: Is ATP an inhibitory neurotransmitter in the rat stomach. Br J Pharmacol. 1975;55 (2) :285P-286P.