Isotopic microassay of histamine, histidine, histidine decarboxylase and histamine methyltransferase in brain tissue.

摘要: — Microassays are described for histamine, histidine, and the activities of enzymes histidine decarboxylase (EC 4.1.1.22) histamine niethyltransferase 2.1.1.8) in brain tissue. The enzymic-isotopic microassay is based on methylation tissue by added methyl-transferase [14C]- or [3H]-labelled S-adenosyl-l-methionine. In a double-isotopic form assay, tracer [3H]histamine employed along with [14C]S-adenosyl-l-methionine, ratio [14C]:[3H] reflects amount sample. Because uniform samples studied, single isotopic assay [3H]S-adenosyl-l-methionine as methyl donor possible increases sensitivity, so that 10 pg can be estimated reliably. involves decarboxylation bacterial measurement formed enzymicisotopic procedure. synthesized from measured. methyltransferase measuring formation [14C]methylhistamine [14C]S-adenosyl-l-methionine serving donor.