Intracellular Inorganic Phosphate and ATP Levels in Human Blood Erythrocytes, Leucocytes and Platelets in Normal Subjects and in Diseases Associated with Altered Phosphate Metabolism

1. The binding of lead to human blood serum, and components of serum, was studied by titration with the addition of Pb(NO3)2 solution, monitoring the free Pb2+ concentration with a Pb2+ electrode, and by equilibrium dialysis. 2. In fresh serum, about 4999 out of 5000 parts of added lead were bound. This suggests that the free Pb2+ concentration is around 1/5000th of the total lead concentration in the serum of normal subjects, i.e. about 1 × 10−12 mol/l. 3. About 60% of the binding of lead in serum is abolished by standing in air, by dialysis or by treatment with N-ethylmaleimide. This appears to be due to the presence of thiol compounds, mainly cysteine. The remaining 40% appears to be due to protein, mainly albumin.

Download Full-text

Vitamin B12, in Human Blood and Serum

Clinical Chemistry ◽

10.1093/clinchem/6.6.578 ◽

1960 ◽

Vol 6 (6) ◽

pp. 578-581 ◽

Cited By ~ 7

Author(s):

Herman Baker ◽

Oscar Frank ◽

Inez Pasher ◽

Harry Sobotka

Keyword(s):

Escherichia Coli ◽

Vitamin B12 ◽

Human Blood ◽

Euglena Gracilis ◽

Whole Blood ◽

Normal Subjects ◽

Lactobacillus Leichmannii

Abstract A comparison of microbiologic assays for vitamin B12 in whole blood or serum was carried out with four B12-requiring microorganisms, Escherichia coli 113-3, Lactobacillus leichmannii ATCC No. 7839, Euglena gracilis, strain Z, and Ochromonas malhamensis. B12 values in whole blood and serum for normal subjects are given. The value of microbiologic assays is discussed.

Download Full-text

Myosin VI deafness mutation prevents the initiation of processive runs on actin

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1420989112 ◽

2015 ◽

Vol 112 (11) ◽

pp. E1201-E1209 ◽

Cited By ~ 19

Author(s):

Olena Pylypenko ◽

Lin Song ◽

Ai Shima ◽

Zhaohui Yang ◽

Anne M. Houdusse ◽

...

Keyword(s):

Actin Filaments ◽

Inorganic Phosphate ◽

Atp Hydrolysis ◽

Hydrolysis Product ◽

Actin Binding ◽

Reverse Direction ◽

Myosin Vi ◽

Cardiac Myosin ◽

Atp Levels

Mutations in the reverse-direction myosin, myosin VI, are associated with deafness in humans and mice. A myosin VI deafness mutation, D179Y, which is in the transducer of the motor, uncoupled the release of the ATP hydrolysis product, inorganic phosphate (Pi), from dependency on actin binding and destroyed the ability of single dimeric molecules to move processively on actin filaments. We observed that processive movement is rescued if ATP is added to the mutant dimer following binding of both heads to actin in the absence of ATP, demonstrating that the mutation selectively destroys the initiation of processive runs at physiological ATP levels. A drug (omecamtiv) that accelerates the actin-activated activity of cardiac myosin was able to rescue processivity of the D179Y mutant dimers at physiological ATP concentrations by slowing the actin-independent release of Pi. Thus, it may be possible to create myosin VI-specific drugs that rescue the function of deafness-causing mutations.

Download Full-text