Protein fractions of smooth muscle, cardiac muscle and striated muscle in dogs

As a basic biochemical study analyzing the sphincter muscle mechanism controlling urination and evacuation, we analyzed protein fractions of 13 muscle extracts from 8 male dogs and calculated the albumin/total protein (A/T) ratio. The A/T ratio of visceral smooth muscle was higher than that of the striated muscle, except in the external sphincter smooth muscle of the urethra. Moreover, urinary sphincter tissues of urinary organ systems were found to have a higher ratio than that of other tissues. Approximately 30 clear protein bands were obtained using sodium dodecyl sulfate-polyacrylamide gel (SDS-PAGE) and these each showed characteristic protein patterns on comparison of visceral smooth muscle with striated muscle. On 2 dimensional SDS-PAGE using visceral smooth muscles, many protein spots were observed on the acidic side, whereas that using striated muscles showed many protein spots on the alkalinic side. As prostate gland and cardiac muscle showed specific characteristics on electrophoretic protein patterns, these muscles could be distinguished from other muscles.