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Sarcolemmae from Chicken Skeletal Muscle. 2. Properties
Author(s) -
HULTIN H. O.,
WESTORT C.
Publication year - 1969
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1969.tb00912.x
Subject(s) - sarcolemma , homogenization (climate) , chemistry , differential centrifugation , centrifugation , biochemistry , skeletal muscle , microsome , phosphatase , membrane , chromatography , enzyme , biology , anatomy , biodiversity , ecology
SUMMARY– Sarcolemmae are usually identified solely by morphological characteristics. We have determined several chemical and enzymic properties of sarcolemmae from chicken breast muscle prepared by homogenization of aged muscle in dilute CaCl 2 solution, washing 4 times in NaCl‐histidine at pH 7.4, extraction with water buffered to pH 7 and isolation by differential centrifugation on a discontinuous sucrose gradient. The phospholipid content of the sarcolemmae was low, representing only 2 to 3% by weight compared with the 20 to 35% usually found in membraneous systems. This discrepancy may be due to the relatively small proportion of plasma membrane in the sarcolemma. Analyses indicate little contamination by nuclei or mitochondria. The sarcolemmae have, like the microsomal fraction, high contents of RNA and glucose‐6‐phosphatase activity. The sarcolemma is either rich in these elements or is contaminated by other subcellular elements, such as the transverse tubules (T system), which are. The sarcolemmae display a Mg +2 ‐ activated ATPase activity which is typical for membraneous systems. Lactate dehydrogenase was shown to be associated with the sarcolemmae. Whether this represents the situation in vivo or is an artifact of preparation is not clear. The sarcolemmae are capable of binding soluble LDH.