Biomedical subjects

L Michelutti

Publications and source records attributed to L Michelutti.

4 recordsLinked to original sources

PubMed1990

Modifications to commercial oxalate oxidase based determination of urinary oxalate: a method suitable for routine clinical analysis.

A commercially available assay (Sigma) for urinary oxalates based on the oxalate oxidase/peroxidase catalyzed reaction produced, in our hands, recoveries of added oxalate that varied from patient to patient. A modification of the assay is reported that involves the chromatographic separation of interfering substances, such as ascorbate and uric acid, from oxalate prior to analysis. With the modification recoveries of added oxalate were essentially complete and showed less patient-to-patient variability. Correlation with an alternate procedure was greatly improved.

Humans↗

PubMed1987

Isolation and purification of creatine kinase conversion factor from human serum and its identification as carboxypeptidase N.

Creatine kinase conversion factor has been isolated from human serum and purified to electrophoretic and chromatographic homogeneity. The enzyme sequentially converts creatine kinase MM3 to MM2 and MM1 and hydrolyzes lysine and arginine from hippuryl-L-lysine and hippuryl-L-arginine. Data on molecular weight, (316,000 dalton), electrophoretic mobility (alpha-globulin), prevalence in serum (26 mg/L), subunit composition (two subunits, 80,000 and 52,200 dalton) indicate that creatine kinase conversion factor is identical to carboxypeptidase N. The previously reported lower molecular weight of 190,000 dalton of partially purified creatine kinase conversion factor is attributed to proteolytic degradation.

Carboxypeptidases↗

PubMed1982

An assay for creatine kinase conversion factor.

The M subunits of creatine kinase (CK) isoenzymes, MM and MB, are subject to a postsynthetic modification in serum. As a result of this modification three sub-bands of MM can be identified by agarose electrophoresis, called MM3, MM2 and MM1 in the order of increasing electrophoretic mobility towards the anode. An assay has been developed for the protein, called creatine kinase conversion factor, which catalyses the reaction leading to the sub-bands. The assay is based on the rate of conversion of MM3 to MM2 and MM1. The first order rate constant for the conversion, designated as kc, for sera of 24 apparently healthy adults ranges from 0.0221 to 0.0740 hr-1 with a mean of 0.0392 hr-1 under the conditions of the assay. Temperature and pH dependence of kc have been determined.

Adult↗

PubMed1981

Studies on the sub-banding of creatine kinase MM and the "CK conversion factor".

In serum, the M subunit of creatine kinase (CK) isoenzymes, MM and MB, is modified by a heat labile factor. As a result of the modification three sub-bands of MM and two of MB can be demonstrated by agarose electrophoresis. Normal sera contain MM1 as the dominant sub-band with lesser amounts of MM2 and MM3. Following tissue damage the MM sub-band distribution changes as a result of the increased release of MM, which occurs as MM3. Immediately after coronary bypass surgery MM3 is the dominant sub-band to be replaced by MM2 and in turn by MM1. The factor responsible for the modification of the M subunit, the "CK conversion factor" has been partially purified and its molecular weight determined.

Biological Products↗