Genetic variants of human serum cholinesterase influence metabolism of the muscle relaxant succinylcholine.

People with genetic variants of cholinesterase respond abnormally to succinylcholine, experiencing substantial prolongation of muscle paralysis with apnea rather than the usual 2-6 min. The structure of usual cholinesterase has been determined including the complete amino acid and nucleotide sequence. This has allowed identification of altered amino acids and nucleotides.

Identification of the structural mutation responsible for the dibucaine-resistant (atypical) variant form of human serum cholinesterase.

A point mutation in the gene for human serum cholinesterase was identified that changes Asp-70 to Gly in the atypical form of serum cholinesterase. The mutation in nucleotide 209, which changes codon 70 from GAT to GGT, was found by sequencing a genomic clone and sequencing selected regions of DNA amplified by the polymerase chain reaction. The entire coding sequences for usual and atypical cholinesterases were compared, and no other consistent base differences were found.

Brain cDNA clone for human cholinesterase.

A cDNA library from human basal ganglia was screened with oligonucleotide probes corresponding to portions of the amino acid sequence of human serum cholinesterase (EC 3.1.1.

Location of disulfide bonds within the sequence of human serum cholinesterase.

Human serum cholinesterase was digested with pepsin under conditions which left disulfide bonds intact. Peptides were isolated by high pressure liquid chromatography, and those containing disulfide bonds were identified by a color assay. Peptides were characterized by amino acid sequencing and composition analysis.

Complete amino acid sequence of human serum cholinesterase.

The complete amino acid sequence of human serum cholinesterase (choline esterase II (unspecific), EC 3.1.1.

Molecular biology of human serum cholinesterase.

More than 90% of the amino acid sequence of purified human serum cholinesterase has been determined in our laboratory. Purified enzyme was digested with several proteolytic enzymes; the resulting polypeptides were then separated, purified, and sequenced. Optimal sequence regions were identified and used as the basis for the synthesis of three 17-mer oligonucleotide probes.

Amino acid sequence of the active site of human serum cholinesterase from usual, atypical, and atypical-silent genotypes.

Active-site tryptic peptides were isolated from three genetic types of human serum cholinesterase. The active-site peptide was identified by labeling the active-site serine with [3H]diisopropylfluorophosphate. Peptides were purified by high-performance liquid chromatography.

Immunological comparison of the usual and atypical human serum cholinesterase phenotypes.

Antiserum prepared against highly purified usual human serum cholinesterase (the most common phenotype) cross-reacted identically with the atypical serum cholinesterase. The level of circulating atypical enzyme protein, determined immunologically, was about 30% lower when the enzyme came from an atypical rather than a usual phenotype, and the level of enzyme activity measured enzymatically at Vmax with either o-nitrophenylbutyrate or benzoylcholine as substrate showed approximately the same degree of reduction. The average specific activity (activity at Vmax per microgram of enzyme protein) in sera from 28 usual and 20 atypical individuals did not differ significantly.

Substance P hydrolysis by human serum cholinesterase.

Highly purified human serum cholinesterase (EC 3.1.1.

Hydrolysis of diacetylmorphine (heroin) by human serum cholinesterase.

The enzyme in human serum that rapidly hydrolyzes diacetylmorphine (heroin) to 6-acetylmorphine is identified in this report as serum cholinesterase (EC 3.1.1.

Comparison of atypical and usual human serum cholinesterase. Purification, number of active sites, substrate affinity, and turnover number.

Atypical and usual human serum cholinesterases were purified and studied with the fluorescent probe, N-methyl-(7-dimethylcarbamoxy)quinolinium iodide. Four active sites per tetramer were found in each enzyme. The turnover numbers of usual and atypical cholinesterases were the same: 15,000 mumol of benzoylcholine hydrolyzed/min/mumol of active site; 48,000 min-1 for o-nitrophenylbutyrate; and 0.

Argininosuccinate synthetase activity in cultured human lymphocytes.

The activity of argininosuccinate synthetase (E.C. 6.

Citrulline metabolism in normal and citrullinemic human lymphocyte lines.

Citrullinemia is one of the five aminoacidurias associated with the Krebs-Henseleit urea cycle. A long-term lymphocyte line (UM-21) derived from a patient with this disease and nine of ten clones of this line were found to have no activity for the enzyme argininosuccinate synthetase (AS), as demonstrated by their inability to grow in medium in which citrulline had been substituted for arginine, by their inability to incorporate arginine-C14 derived from citrulline-C14 into cellular protein, and by direct enzyme assay. One clone had normal or nearly normal argininosuccinate synthetase activity, as demonstrated by the same criteria.